A inversão do sexo em peixes hermafroditas sequenciais (protândricos ou protogínicos) ocorre em decorrência de diversos fatores, dentre eles, fisiológicos, genéticos, podendo ser ainda decorrência do comportamento social. Nos peixes hermafroditas marinhos as alterações sexuais são acompanhadas por alterações anátomo-funcionais das gônadas, coloração e comportamento dos animais. A espécie Epinephelus marginatus (garoupa verdadeira), serranídeo da fauna nativa e amplamente difundida no litoral brasileiro, é um hermafrodita protogínico que apresenta dificuldade na manutenção de indivíduos do sexo masculino em seus cardumes e, além disso, encontra-se na lista de espécies sobreexplotadas. Utilizando-se técnicas de inversão sexual induzida, em cativeiro, para a obtenção de machos, este trabalho teve como objetivo estudar as alterações de alguns tecidos endócrinos durante o processo de inversão sexual, utilizando tratamentos com inibidores de aromatase (AI) e metiltestosterona (MT) em animais jovens. Ao longo de 90 dias de experimento a utilização do AI e do MT promoveu uma aparente desorganização da arquitetura gonadal padrão, massiva degeneração das células germinativas femininas, surgimento de centros melanomacrofágicos, proliferação de estruturas associadas ao sexo masculino (tecido intersticial e células germinativas masculinas) e a maturação das células germinativas masculinas. A utilização do andrógeno sintético MT (sozinho ou combinado com AI) possibilitou a obtenção de gônadas em fases mais avançadas de espermatogênese, inclusive a fase de espermiogênese inicial, com redução significativa dos valores do índice gonadossomático (IGS). Já com a utilização do AI foram encontradas gônadas em processos de intersexo mais clássicos após 90 dias experimentais. As análises de imunomarcação das células gonadotrópicas hipofisárias foram viáveis utilizando-se anticorpos de salmão e os resultados mostraram que as células produtoras de FSH (hormônio folículo-estimulante) e LH (hormônio luteinizante) distribuem-se pela proximal pars distalis e pars intermedia da adenohipófise. Os resultados obtidos com as análises imunohistoquímicas da hipófise demonstraram uma marcação de pouca intensidade utilizando-se o anticorpo anti-βFSH no grupo tratado com AI após 90 dias. A análise dos esteróides gonadais mostrou que nos animais tratados com AI, não houve diminuição na concentração do estradiol aos 90 dias, desta forma a alça de feedback negativo provavelmente foi acionada, e a produção de FSH diminuiu, causando o aumento da concentração plasmática de 11 cetotestosterona (11 KT) (via ação do LH). Já nos grupos onde o MT foi administrado, houve uma diminuição na concentração de estradiol após o tratamento, causando possivelmente uma menor intensidade na alça de feedback negativo na hipófise, sendo a ação do andrógeno sintético mais efetiva na espermiogênese nestes animais. As análises das gônadas e da hipófise sugerem a atuação do FSH no início da transição do sexo, sendo proposta a liberação desta glicoproteína como o gatilho para a inversão sexual em hermafroditas protogínicos. Estudos mais detalhados ao longo dos 90 dias de transição gonadal em E. marginatus precisam ser realizados para constatar o real envolvimento do FSH na inversão do sexo e verificar se a liberação do LH estaria envolvida com a produção de 11-ceto-testosterona, a espermiogênese completa e espermiação / The sex inversion in sequential hermaphrodite fish (protandrous or protogynous) occurs due to several factors, including physiological, genetics, and also can be associated with the social behavior. In marine hermaphrodite fish, the sex alterations are followed by anatomic and functional alterations in the gonads, color patterns and animal behavior. The species Epinephelus marginatus (dusky grouper), a native serranid and broadly distributed in the Brazilian coast, is a protogynous with problems in maintaining males in the shoal and, additionally, this species is part of the overexploited marine fish red list. Induction of sex change, in captivity, using aromatase inhibitors (AI) and 17α-methyltestosterone (MT) has been conducted with the purpose to study the morphophysiological alteration in some endocrine tissues in juveniles. During 90 experimental days, the use of AI and MT promoted an apparent disorganization of the standard gonad architecture, a massive degeneration of the female germ cells, the appearance of melanomacrophagic centers, a proliferation of the structures associated with the male sex (interstitial tissue and male germ cells) and the maturation of male germ cells. The use of the synthetic androgen, MT (alone or combined with AI) allowed the obtaining of gonads in a more advanced spermatogenesis phase, including an initial spermiogenesis phase, with a significant reduction of gonadossomatic index (GSI). With the use of AI, the gonads were found in a more classic intersex process after 90 days of experiment. The immunostaining analysis of the gonadotropic cells were viable using salmon antibodies and the results showed that FSH and LH cells were distributed in proximal pars distalis and pars intermedia in adenohypophysis. The immunohistochemistry analysis of the pituitary showed a low intensity of staining with the anti-βFSH in the AI group, after 90 experimental days. The analysis of the gonad steroids showed that in the animals from the AI group, there was no decrease in estradiol levels after 90 days, so the negative feedback loop probably was activated, the FSH secretion decreased, allowing the increase of plasma 11- ketotestosterone (11KT) (through LH action). In the MT groups there was a decrease in plasma estradiol, what probably decreased the intensity of the negative feedback loop in the pituitary, and in this case, the action of the synthetic androgen was predominant in spermiogenesis. The analysis of the gonads and pituitary suggest the action of FSH in the beginning of the sex transition, with the proposal that this glycoprotein acts triggering the sex inversion in protogynous hermaphrodites. We suggest that more detailed studies during the 90 days of gonad transition in E. marginatus must be done in order to find the real involvement of FSH in sex inversion and to elucidate the actual role of LH with 11KT production, the full spermiogenesis and spermiation

A plasticidade do desenvolvimento gonadal em peixes, que contrasta com os padrões mais estáveis encontrados nos demais vertebrados, deu origem a várias questões intrigantes relativas tanto ao seu significado adaptativo quanto aos fatores genéticos e fisiológicos que modulam o processo. A inversão do sexo em peixes hermafroditas seqüenciais (protândricos ou protogínicos) ocorre em decorrência de diversos fatores, dentre eles, fisiológicos, genéticos e comportamentais podendo ser ainda decorrente do comportamento social. A garoupa verdadeira, Epinephelus marginatus é um peixe teleósteo, hermafrodita protogínico característico do litoral rochoso, maturando primeiramente como fêmeas, e posteriormente, na vida adulta, os ovários são substituídos por testículos, transformando-os em machos reprodutivamente ativos. No presente trabalho foram realizados três experimentos de inversão sexual em condições assistidas, em diferentes estações do ano, utilizando a mesma dose do inibidor de aromatase (IA) letrozole (100μg/Kg) para promover a inversão sexual de E. marginatus visando contribuir e aprimorar o conhecimento dos mecanismos fisiológicos envolvidos nesse processo. O primeiro e o terceiro experimentos foram iniciados na primavera e início da primavera respectivamente e promoveram a inversão sexual com uma diminuição no índice gonadossomático (IGS) nos animais do grupo experimental que apresentaram uma desorganização gonadal peculiar, com lamelas características de ovário, no entanto em seu interior observou-se o compartimento intersticial desenvolvido com cistos de células germinativas masculinas em estágios avançados da espermatogênese, (espermatócitos, espermátides) células de Sertoli e grande quantidade de cistos rompidos com a liberação de espermatozoides no lúmen. Após trinta dias do início do experimento obteve-se um aumento significativo de 11 ceto-testosterona (11KT) e a concentração de estradiol (E2) permaneceu inalterada; com setenta e sete dias após o início do experimento constatou-se uma elevação na concentração de testosterona (T), uma queda nos níveis de 11KT, persistindo a manutenção na concentração de E2. Neste cenário, principalmente as concentrações de andrógenos podem ter ativado a alça de feedback negativo e juntamente com a ativação do sistema da kisspeptina podem ter promovido a ação do GnRH desviando a produção de FSH para LH. Nesse momento o número de cópias obtidas de βFSH na hipófise foi significativamente menor que o número encontrado no grupo controle. Ao observarmos o aumento significativo da concentração plasmática de 17-alfaOHprogesterona podemos sugerir que a ação do GnRH tenha aumentado a secreção do LH, principal gonadotropina que estimula a produção de progestágenos. Os machos invertidos produziram um volume médio de sêmen de 118,20 ± 24,83 μL com motilidade de 90% e densidade espermática de 8,94 ± 4,34 x 109 células mL-1. Não foram obtidas diferenças nas concentrações de proteínas totais plasmática, hepática e musculares. No experimento implantado no verão de 2010 o tratamento não promoveu a inversão sexual, o IGS não apresentou diferença significativa entre os animais tratados com inibidor de aromatase e os animais do grupo controle. Nas gônadas dos animais do grupo experimental foi observada uma ligeira desorganização da arquitetura gonadal com cistos em formação e um número grande de ovócitos em degeneração demonstrando que ao longo do processo de inversão sexual pode haver uma fase de intersexo. Após trinta dias do início do experimento obteve-se um aumento significativo de T e a concentração de E2 permaneceu inalterada. Não foram observadas diferenças significativas entre o número de cópias de βFSH e βLH ao longo do experimento. O resultado obtido para a concentração de proteínas totais do músculo dos animais do grupo experimental apresentou um aumento significativo em relação à concentração encontrada nos animais do grupo controle. Não ocorreu espermiação e a inversão se deu de forma incompleta promovendo indivíduos intersexo. De uma forma geral podemos concluir que o uso de inibidor de aromatase é um método eficaz para promover a inversão sexual em hermafroditas protogínicos como a garoupa verdadeira. O aumento dos andrógenos pode ser o gatilho da inversão sexual com papel fundamental na reestruturação gonadal e formação do tecido germinativo masculino neste processo / The plasticity of gonadal development in fish, which contrasts with the more stable patterns found in other vertebrates, has given rise to several thrilling questions concerning both, its adaptive significance regarding the genetic and physiological factors that modulate the process. The sex inversion in sequential hermaphrodites fish (protandrous or protogynuos) occurs due to several factors, including, physiological, genetic and behavioral, and may also be due to social behavior. The dusky grouper, Epinephelus marginatus is a teleost fish, protogynous hermaphrodite characteristic of rocky bottoms, maturing first as females and later in adult life, the ovaries are replaced by the testes, turning them into reproductively males. In this work three sex inversion experiments were performed in captivity in different seasons of the year, using the same dose of aromatase inhibitor (AI) letrozole (100μg/Kg) to promote sexual inversion in E. marginatus, to contribute and improve the knowledge of the physiological mechanisms involved in this process. The first and third experiments started in the spring and early spring, respectively and promoted sexual inversion with a decrease in the gonadosomatic index (GSI) in the animals from the experimental group, that showed a peculiar disorganized gonadal, with lamellae, characteristic from ovaries, however with an interstitial compartment developed with cysts of male germ cells in advanced stages of spermatogenesis (spermatocytes, spermatids), Sertoli cells and a large amount of cysts ruptured with the release of sperm in the lumen. After thirty days from the beginning of the experiment, there was an increase in 11- ketotestosterone (11KT) levels and an unchanged concentration of estradiol (E2); after seventy-seven days, there was a significant increase in testosterone (T) levels, a decrease in the 11KT levels and the maintenance of E2 plasma concentration. In this point of view, mainly the concentration of androgens may have activated the negative feedback loop and with the activation of the kisspeptin system may have promoted the action of GnRH diverting the production of FSH to LH. At this moment the number of copies of pituitary βFSH produced was ignificantly lower than the number of control group copies. The significant increase in plasma 17- alfaOHprogesterona concentration observed could suggest that the action of GnRH has increased the secretion of LH, the main gonadotropin that stimulates the production of progestogen. Inverted males produced an average volume of semen of 118.20 ± 24.83 μl with 90% motility and sperm density of 8.94 ± 4.34 x 109 cells.ml-1. No differences were obtained at the concentrations of total protein in plasma, liver and muscle. In the experiment established in the summer of 2010, the treatment did not promote sexual inversion, the GSI was not significantly different between animals treated with aromatase inhibitor and the control group. In the gonads of the animals from the experimental group there was a slight disruption of gonadal architecture with cysts in formation and a large number of degenerating oocytes showing that during the process of sex inversion may be a phase of intersex. Thirty days after the beginning of the experiment there was a significant increase of T and E2 concentration remained unchanged. No significant differences were observed between the number of copies of βFSH and βLH throughout this experiment. The result obtained for the total protein concentration of the muscle in experimental group showed a significant increase compared with the control animals. There was no spermiation and the sex inversion occurred incompletely, with the presence of intersex individuals. In general we could conclude that the use of an aromatase inhibitor is an effective method to promote the sex inversion in hermaphroditic protogynous as the groupers. The increase of androgens could trigger the sex inversion exerting an important role in gonadal restructuring and the development of male germ tissue in the process

O alumínio (Al) é o metal mais abundante na natureza e tornou-se importante poluente aquático trazendo prejuízos a reprodução de teleósteos, atuando como um desregulador endócrino. No entanto, em experimentos in vivo não é possível demonstrar que os efeitos do Al no eixo endócrino reprodutivo são devido a sua atuação direta sobre os órgãos que o compõem. Por isso, este trabalho teve como objetivo avaliar o efeito direto do Al sobre células foliculares ovarianas, gonadotrópicas e somatolactínicas hipofisárias de fêmeas maduras de Oreochromis niloticus. Para isso dois experimentos in vitro de exposição ao Al foram realizados: um utilizando-se ovários maduros e outro hipófises de fêmeas sexualmente maduras. Para os experimentos ovarianos, frações de ovários maduros foram incubadas por 4 horas formando os seguintes grupos: 1) Grupo controle (Ctr): tecido ovariano exposto somente à solução de Krebs-Ringer-glucose-HEPES; 2) Grupo gonadotropina coriônica humana (hCG): tecido exposto à 6 µg/ml de hCG (Ovidrel); 3) Grupo (hCG+Al): tecido exposto à 6 µg/ml de hCG (Ovidrel) + cloreto de alumínio (AlCl3) - 10mM; 4) Grupo (Al): exposto somente ao AlCl3 - 10mM. A concentração dos hormônios 17β-estradiol (E2) e 17α-hidroxiprogesterona (17αOHP) no meio de incubação foi determinada por ELISA. Para os experimentos hipofisários, hipófises de fêmeas sexualmente maduras foram incubadas por 24 horas formando os seguintes grupos: 1) Ctr: hipófise exposta somente ao meio L15 (controle interno); 2) GnRH: hipófise exposta somente ao GnRH (controle de liberação de gonadotropinas); 3) GnRH+Al: hipófise exposta ao GnRH + AlCl3 10mM e 4) Al: hipófise exposta somente AlCl3 10mM. Após o período experimental, foram realizadas análises de qPCR (PCR quantitativo), análises de imunohistoquímica, e de microscopia eletrônica. Os resultados do experimento ovariano mostraram que os fragmentos ovarianos do grupo exposto à hCG apresentaram um aumento significativo da liberação dos hormônios E2 e 17αOHP em relação aos demais grupos, confirmando o efeito desta gonadotropina sintética na liberação destes esteroides gonadais. No entanto, a administração conjunta da hCG com Al (hCG+Al) não gerou este aumento da produção dos esteroides em relação ao grupo controle. Estes dados evidenciam que o Al inibiu a resposta celular das células esteroidogênicas ovarianas às gonadotropinas. Os resultados dos experimentos hipofisários mostraram que o Al (GnRH+Al e Al) afetou a expressão gênica dos genes estudados (βFSH, (βLH, SL) inclusive dos normalizadores (EF1α e (βAc), o que tem sido comum em experimentos de ecotoxicologia. Os dados de microscopia eletrônica mostraram desestruturação celular nas hipófises que foram expostas ao Al e as análises de imunohistoquímica apontaram que o Al (GnRH+Al e Al) não interferiu sobre a quantidade de grânulos de βLH e SL, enquanto o grupo Al indicou uma diminuição na quantidade de grânulos de βFSH, sugerindo que o Al afeta a dinâmica de síntese/liberação desta gonadotropina. Estes dados evidenciam a toxicidade do Al diretamente sobre ambos os órgãos estudados, tanto em nível de resposta celular quanto em nível estrutural confirmando o potencial do Al como um DE e amplia as perspectivas de estudo sobre o mecanismo de ação do Al como um DE / Aluminum (Al) is the most abundant metal in nature and has become an important water pollutant impairing reproduction of teleosts, acting as an endocrine disrupter. However, in vivo experiments cannot demonstrate that the effects of Al on the reproductive endocrine axis are due to direct action on the organs that compose it. Therefore, this study aimed to assess the direct effect of Al on ovarian follicular cells, gonadotropic and somatolactin pituitary cells of mature females of O. niloticus. For this, two in vitro exposure experiments of Al were performed: one using mature ovaries and other using pituitaries of sexually mature females. For ovarian experiments, fractions of mature ovaries were incubated for 4 hours to obtain the following groups: 1) control group (Ctr): ovarian tissue only exposed to Krebs- Ringer-HEPES-glucose; 2) human chorionic gonadotropin (hCG) group: tissue exposed to 6 mg/ml hCG (Ovidrel); 3) hCG + Al group: tissue exposed to 6 mg/ml hCG (Ovidrel) + aluminum chloride (AlCl3) - 10mM; 4) Al group: only exposed to 10 mM AlCl3. The concentration of the hormones 17β-estradiol (E2) and 17α-hydroxyprogesterone (17αOHP) in the incubation medium was determined by ELISA. For pituitary experiments, pituitaries of sexually mature females were incubated for 24 hours to form the following groups: 1) Ctr: pituitary exposed only to L15 (internal control); 2) GnRH: only exposed to the pituitary GnRH (gonadotropin releasing hormone); 3) GnRH + Al: exposed to the pituitary GnRH AlCl3 + 10 mM and 4) Al: 10mM AlCl3 only exposed pituitary. After the assay period, analysis of qPCR (quantitative PCR), analysis of immunohistochemistry and electron microscopy were performed. The results of the experiment showed that the ovarian exposed to hCG group showed a significant increase in the release of E2 and 17αOHP compared to the other groups, confirming the effect of synthetic gonadotropin in the release of these gonadal steroids. However, the administration combined of hCG with Al (Al + hCG) did not generate this increased production of steroids compared with the control group. These data show that Al inhibited the cellular response of the ovarian steroidogenic cells to gonadotropins. The results of the experiments with pituitaries showed that Al (GnRH + Al and Al) affected the gene expression of the genes studied (βFSH, (βLH, SL) including the house keeping genes (EF1α and βAc), what has been common in ecotoxicology experiments. Data from electron microscopy showed cell disruption in the pituitary glands that were exposed to Al and immunohistochemical analyzes showed that Al (GnRH + Al and Al) did not affect the amount of granules of βLH and SL, while the Al group indicated a decrease the amount of βFSH granules, suggesting that Al affects the dynamics of the synthesis/release of this gonadotropin. These data show the toxicity of Al directly on both organs studied, at both the cellular response as for structural level confirming the potential of Al as a DE and increases the perspectives of study on the mechanism of action of Al as a DE

Einfluss des Wachstumsfaktors Insulin-like growth factor-I (IGF-I) auf das Follikelwachstum beim Weißbüschelaffen (Callithrix jacchus) Aus dem Veterinär-Physiologisch-Chemischen Institut der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im September 2010 (86 S., 16 Abb., 9 Tab., 225 Lit., 4 S. Anhang) Schlüsselwörter: Insulin-like Growth Factor-I (IGF-I), Granulosazellen, Steroidhormone (Östradiol, Progesteron), Gonadotropine (FSH, hCG) In der vorliegenden Studie wurde die Rolle von IGF-I und das Zusammenwirken mit den Gonadotropinen (FSH, hCG) auf die Sekretion der Steroidhormone (Progesteron, Östradiol) kultivierter Granulosazellen von 13 Weißbüschelaffen untersucht, um zu prüfen, ob und wie weit IGF-I die Sekretion und Reifung der Granulosazellen beeinflusst. Für die in vitro-Experimente wurden Zellkulturen mit Granulosazellen kleiner ( 0,5 - 1 mm) und präovulatorischer Follikel ( > 2 mm) von Ovarien am 7. Tag der Follikelphase verwendet. Vor jedem Versuch wurde das Wachstum der Follikel durch zwei Ultraschalluntersuchungen kontrolliert. Während der Kultur wurden drei Inkubationsintervalle von je 48 h durchgeführt. Die Zellen wurden mit IGF-I allein oder in Kombination mit FSH bzw. hCG stimuliert. Zum Teil wurden die Gonadotropine auch zur Prästimulation verwendet. Das Signifikanzniveau der Hormoneffekte lag bei p<0,05. Bei den Granulosazellen kleiner Follikel lässt sich durch die alleinige Gabe von IGF-I nur am Ende der Kultur (144 h) eine signifikante Erhöhung der Progesteronsekretion feststellen. Bei einer Kombinationsgabe von IGF-I und FSH findet sich schon am Anfang (48 h) ein signifikanter Einfluss auf die Sekretion von Progesteron und Östradiol. Bei der Progesteronsekretion ist der Effekt der Kombination signifikant höher als bei Einzelgabe beider Hormone. Dagegen ist bei der Östradiolsekretion der Effekt der Kombination zwar nicht höher als bei einer alleinigen Gabe von FSH, aber die Zellen reagieren wesentlich schneller auf IGF-I, wenn sie zusammen mit FSH stimuliert werden. Keine signifikante Wirkung in der Steroidhormonsekretion ruft die Hormonkombination IGF-I und hCG im Vergleich zur alleinigen Gabe der beiden Hormone hervor. Bei dem Vergleich beider Gonadotropine ist eine signifikante Erhöhung der Steroidhormonsekretion nur bei alleiniger Gabe von FSH zu beobachten. Bei den Experimenten mit Prästimulationen (FSH oder hCG) lässt sich nur bei der FSH-Prästimulation mit einer nachfolgenden Kombinationsgabe von hCG und IGF-I eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Dies bedeutet, dass FSH die kleinen Granulosazellen auf die Wirkung von hCG sensibilisiert, wobei IGF-I diesen Vorgang unterstützt. Im Gegensatz zu den kleinen Follikeln lässt sich bei den Granulosazellen der präovulatorischen Follikel ein signifikanter Effekt von verschiedenen Hormonstimulationen schon früh beobachten. Durch alleinige IGF-I-Gabe lässt sich bereits am Anfang der Kultur (48 h) eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Eine Kombinationsgabe von IGF-I und der Gonadotropine (FSH oder hCG) zeigt, dass die Kombination mit FSH zu einer signifikanten Erhöhung beider Steroide im Vergleich zur Kontrolle führt. Dagegen zeigt sich bei einer Kombination von IGF-I und hCG eine signifikante Erhöhung der Steroidhormonsekretion schon ab 48 h sowohl im Vergleich zur Kontrolle als auch zur alleinigen Gabe dieser Hormone. Bei der Untersuchung des Effekts beider Gonadotropine (FSH oder hCG) ist schon ab 48 h ein signifikanter Effekt auf beide Steroidhormone zu erkennen. Beide Gonadotropinprästimulationen (FSH oder hCG) mit nachfolgender Hormonkombination (hCG und IGF-I) führen bei den Granulosazellen der präovulatorischen Follikel zu einer signifikant geringeren Steroidhormonsekretion im Vergleich zur Gabe von hCG und IGF-I ohne Prästimulation. Die Zellen reagieren offenbar in dieser Art und Weise, um eine mögliche übermäßige Steroidgenese, und somit eine pathologische Situation, zu verhindern. Die vorliegende Arbeit zeigt, dass IGF-I bei den kleinen und präovulatorischen Follikeln unterschiedliche Wirkungen hervorruft. Es scheint, dass IGF-I die Sekretion von Progesteron und Östradiol auf unterschiedliche Art und Weise beeinflusst, und dass die Granulosazellen der Weißbüschelaffen erst während der Follikelentwicklung die Fähigkeit erwerben, auf IGFI entsprechend zu reagieren. Die Ergebnisse zeigen weiterhin, dass IGF-I bei den Granulosazellen der kleinen Follikel eine eher unterstützende Rolle für die Gonadotropine spielt, und dass IGF-I mit den Gonadotropinen bei der Reifung und der Differenzierung der Follikel mitwirkt. Möglicherweise spielt IGF-I auch während der Entwicklung und des Wachstums des präovulatorischen Follikels sowie bei der Regulierung der Progesteronsekretion eine Rolle. Die vorliegenden Ergebnisse unterstützen die Hypothese, dass IGF-I zusammen mit hCG die Zelldifferenzierung bei den Granulosazellen der präovulatorischen Follikel fördert. Außerdem kann vermutet werden, dass bei den Granulosazellen der präovulatorischen Follikel IGF-I zusammen mit FSH in unabhängiger Weise wirkt. Abschließend kann gesagt werden, dass ein Zusammenwirken zwischen den Gonadotropinen und IGF-I in Bezug auf die Bildung des präovulatorischen Follikels und die darauffolgende Ovulation existiert, dies gilt es auch bei pathologischen Situationen der Follikelreifung und Ovulation zu berücksichtigen.

O alumínio (Al) é o metal mais abundante na natureza e tornou-se importante poluente aquático trazendo prejuízos a reprodução de teleósteos, atuando como um desregulador endócrino. No entanto, em experimentos in vivo não é possível demonstrar que os efeitos do Al no eixo endócrino reprodutivo são devido a sua atuação direta sobre os órgãos que o compõem. Por isso, este trabalho teve como objetivo avaliar o efeito direto do Al sobre células foliculares ovarianas, gonadotrópicas e somatolactínicas hipofisárias de fêmeas maduras de Oreochromis niloticus. Para isso dois experimentos in vitro de exposição ao Al foram realizados: um utilizando-se ovários maduros e outro hipófises de fêmeas sexualmente maduras. Para os experimentos ovarianos, frações de ovários maduros foram incubadas por 4 horas formando os seguintes grupos: 1) Grupo controle (Ctr): tecido ovariano exposto somente à solução de Krebs-Ringer-glucose-HEPES; 2) Grupo gonadotropina coriônica humana (hCG): tecido exposto à 6 µg/ml de hCG (Ovidrel); 3) Grupo (hCG+Al): tecido exposto à 6 µg/ml de hCG (Ovidrel) + cloreto de alumínio (AlCl3) - 10mM; 4) Grupo (Al): exposto somente ao AlCl3 - 10mM. A concentração dos hormônios 17&beta;-estradiol (E2) e 17&alpha;-hidroxiprogesterona (17&alpha;OHP) no meio de incubação foi determinada por ELISA. Para os experimentos hipofisários, hipófises de fêmeas sexualmente maduras foram incubadas por 24 horas formando os seguintes grupos: 1) Ctr: hipófise exposta somente ao meio L15 (controle interno); 2) GnRH: hipófise exposta somente ao GnRH (controle de liberação de gonadotropinas); 3) GnRH+Al: hipófise exposta ao GnRH + AlCl3 10mM e 4) Al: hipófise exposta somente AlCl3 10mM. Após o período experimental, foram realizadas análises de qPCR (PCR quantitativo), análises de imunohistoquímica, e de microscopia eletrônica. Os resultados do experimento ovariano mostraram que os fragmentos ovarianos do grupo exposto à hCG apresentaram um aumento significativo da liberação dos hormônios E2 e 17&alpha;OHP em relação aos demais grupos, confirmando o efeito desta gonadotropina sintética na liberação destes esteroides gonadais. No entanto, a administração conjunta da hCG com Al (hCG+Al) não gerou este aumento da produção dos esteroides em relação ao grupo controle. Estes dados evidenciam que o Al inibiu a resposta celular das células esteroidogênicas ovarianas às gonadotropinas. Os resultados dos experimentos hipofisários mostraram que o Al (GnRH+Al e Al) afetou a expressão gênica dos genes estudados (&beta;FSH, (&beta;LH, SL) inclusive dos normalizadores (EF1&alpha; e (&beta;Ac), o que tem sido comum em experimentos de ecotoxicologia. Os dados de microscopia eletrônica mostraram desestruturação celular nas hipófises que foram expostas ao Al e as análises de imunohistoquímica apontaram que o Al (GnRH+Al e Al) não interferiu sobre a quantidade de grânulos de &beta;LH e SL, enquanto o grupo Al indicou uma diminuição na quantidade de grânulos de &beta;FSH, sugerindo que o Al afeta a dinâmica de síntese/liberação desta gonadotropina. Estes dados evidenciam a toxicidade do Al diretamente sobre ambos os órgãos estudados, tanto em nível de resposta celular quanto em nível estrutural confirmando o potencial do Al como um DE e amplia as perspectivas de estudo sobre o mecanismo de ação do Al como um DE / Aluminum (Al) is the most abundant metal in nature and has become an important water pollutant impairing reproduction of teleosts, acting as an endocrine disrupter. However, in vivo experiments cannot demonstrate that the effects of Al on the reproductive endocrine axis are due to direct action on the organs that compose it. Therefore, this study aimed to assess the direct effect of Al on ovarian follicular cells, gonadotropic and somatolactin pituitary cells of mature females of O. niloticus. For this, two in vitro exposure experiments of Al were performed: one using mature ovaries and other using pituitaries of sexually mature females. For ovarian experiments, fractions of mature ovaries were incubated for 4 hours to obtain the following groups: 1) control group (Ctr): ovarian tissue only exposed to Krebs- Ringer-HEPES-glucose; 2) human chorionic gonadotropin (hCG) group: tissue exposed to 6 mg/ml hCG (Ovidrel); 3) hCG + Al group: tissue exposed to 6 mg/ml hCG (Ovidrel) + aluminum chloride (AlCl3) - 10mM; 4) Al group: only exposed to 10 mM AlCl3. The concentration of the hormones 17&beta;-estradiol (E2) and 17&alpha;-hydroxyprogesterone (17&alpha;OHP) in the incubation medium was determined by ELISA. For pituitary experiments, pituitaries of sexually mature females were incubated for 24 hours to form the following groups: 1) Ctr: pituitary exposed only to L15 (internal control); 2) GnRH: only exposed to the pituitary GnRH (gonadotropin releasing hormone); 3) GnRH + Al: exposed to the pituitary GnRH AlCl3 + 10 mM and 4) Al: 10mM AlCl3 only exposed pituitary. After the assay period, analysis of qPCR (quantitative PCR), analysis of immunohistochemistry and electron microscopy were performed. The results of the experiment showed that the ovarian exposed to hCG group showed a significant increase in the release of E2 and 17&alpha;OHP compared to the other groups, confirming the effect of synthetic gonadotropin in the release of these gonadal steroids. However, the administration combined of hCG with Al (Al + hCG) did not generate this increased production of steroids compared with the control group. These data show that Al inhibited the cellular response of the ovarian steroidogenic cells to gonadotropins. The results of the experiments with pituitaries showed that Al (GnRH + Al and Al) affected the gene expression of the genes studied (&beta;FSH, (&beta;LH, SL) including the house keeping genes (EF1&alpha; and &beta;Ac), what has been common in ecotoxicology experiments. Data from electron microscopy showed cell disruption in the pituitary glands that were exposed to Al and immunohistochemical analyzes showed that Al (GnRH + Al and Al) did not affect the amount of granules of &beta;LH and SL, while the Al group indicated a decrease the amount of &beta;FSH granules, suggesting that Al affects the dynamics of the synthesis/release of this gonadotropin. These data show the toxicity of Al directly on both organs studied, at both the cellular response as for structural level confirming the potential of Al as a DE and increases the perspectives of study on the mechanism of action of Al as a DE

The control of reproductive cycles in higher primates is largely dependent on negative and positive feedback mechanisms by both steroidal and non-steroidal substances of the ovaries which regulate the function of hypothalamo-pituitary system. To gain insights into the role of INH A, the non steroidal ovarian hormone in the feedback control of pituitary FSH secretion, studies were conducted to examine the interrelationships of hormones throughout the menstrual cycle of the bonnet macaque. The findings of chapter II provide a detailed description of endocrine hormone profile during the menstrual cycle of the bonnet macaques with special attention to the feedback role of INH A on pituitary FSH secretion. To characterize the endocrine profile of different hormones, both ovarian (E2, P4, INH A) and pituitary (FSH, LH) hormones were measured daily for more than 40 days. To further examine the site of secretion of INH A and its relationship with pituitary FSH dynamics, surgical lutectomy and pharmacological induction of luteolysis employing the third generation GnRH R antagonist, Cetrorelix (CET) studies were carried out in the subsequent experiments. The results obtained from these studies suggest that INH A and P4 secreted from the CL during luteal phase regulate pituitary FSH secretion. The selective rise in FSH observed during the late menstrual cycle and during menstruation (referred to as luteo-follicular transition), as has been reported previously in higher primates, considered necessary for initiation of follicular growth and recruitment of follicles for ensuing menstrual cycle was characterized in the monkey. Surgical lutectomy and induction of luteolysis by CET experiments suggested that increased GnRH secretion is essential for this selective rise in FSH following withdrawal of inhibition by P4 and INH A. In clinical cases of reproductive ageing, the shortened follicular phase in human females has been identified to be the result of occurrence of early onset of FSH rise during the luteal-follicular transition period. The cause(s) of declining fertility with age in women who still have regular menstrual cycles are not clear, but issues of relationship between dysregulation of selective FSH rise in the late luteal phase and associated infertility could be examined using bonnet monkey as a model system. INH A is secreted in significant quantities by CL in higher primates and the feto placental unit suggesting its importance during fertility and pregnancy. Apart from the negative feedback regulation of pituitary FSH secretion, the complete repertoire of actions of this hormone during pregnancy is yet to be fully understood. The data presented in this thesis is the first comprehensive report showing the endocrine hormone profile of gonadotropins and ovarian hormones including INH A throughout the menstrual cycle of the bonnet macaque. The characterization of INH A profile in bonnet monkey will be of significant value for studies examining the role of INH A in higher primates. Dimeric inhibin has been suggested to be important for regulation of fertility and reproductive functions. Also, inhibin-α (one of the subunits of the dimeric protein) knock out mice model has provided convincing evidence that it acts as a tumour suppressor. A great deal of new information has been generated in recent years regarding the potential clinical usefulness of monitoring inhibin levels in blood and biological fluids in gynaecological diseases, pathological pregnancies and other disorders. Emerging clinical roles of inhibin have made INH A an important candidate molecule to study its molecular regulation. The results presented in chapter II suggested that LH regulates luteal INH A secretion (induction of luteolysis by CET administration experiment). As a first step towards understanding molecular regulation of inhibin-α expression in the macaque CL, in silico promoter analysis of macaque inhibin-α was performed and it revealed several transcriptional factor binding sites that were conserved across species. In rats FSH up regulates while preovulatory LH surge suppresses inhibin-α mRNA expression in the ovary and this suppression has been suggested to be necessary for occurrence of secondary FSH surge during metestrus. To address differential regulation of inhibin-α by LH and FSH in rat ovary during the periovulatory period, studies employing immature rats were carried out and the results are presented in chapter III. The results suggest that immature rat ovaries respond to exogenous gonadotropins in terms of LH signaling (cAMP production), luteinization (P4 production) and as well induction of ICER expression required for repression of inhibin-α subunit expression. PDE4 inhibitor (rolipram) treatment enhanced the ovarian cAMP concentrations suggesting that PDE4 play a major role in controlling intraovarian cAMP concentrations in rat ovaries. However increased cAMP concentrations did not appear to up regulate the ICER expression at the time point examined in this study. In higher primates time course of second FSH surge and continued synthesis and secretion of INH A in the CL are different from non primate species. In the monkey, the second FSH rise occurs during the late luteal phase and experiments have been carried out to examine the regulation of inhibin-α subunit expression by ICER. Expressions of ICER (mRNA/protein) and INH A were examined during different stages of CL and the results indicated no clear inverse relationship between the ICER and inhibin-α mRNAs. With no conclusive role for the ICER in regulating luteal inhibin-α observed in the study, the role of transcriptional activators in the regulation of inhibin-α like GATA4, SF-1, β-catenin were further examined. Since luteal INH A secretion was dependent on pituitary LH as determined earlier in chapter II, expressions of transcriptional activators were examined in CL of different stages and also during induced luteolysis and the results are described in chapter IV. In conclusion, our results indicate cross talk between WNT, cAMP and P38 MAP kinase signaling pathways in the regulation of luteal INH A secretion. The pituitary gonadotropin, LH, is the primary luteotropin in primate species acting to maintain the structure and function of the CL during the menstrual cycle. However whether the actions of LH are direct or mediated by local factors such as P4 remain unknown. Moreover, P4 secretion which is dominant during luteal phase has any role in regulating CL structure and function is not clearly defined. To address these and issues concerning P4 actions, initially, experiments were performed in the rat model to study the importance of P4 in the regulation of ovarian functions. An antiprogestin, RU486, was employed as a tool to uncover the PR regulated pathways during ovulation in rats and the findings are presented in the chapter V. The results indicated that blockade of PR action by RU486 during gonadotropin-induced superovulation resulted in inhibition of follicular rupture and ovulation in immature rats. Further to understand the downstream effectors of PR action, and to identify the candidate target genes of PR activation, semi-quantitative RT-PCR and western blot analyses were performed. The results obtained indicated that betacellulin, a member of EGF family and MMP-9 a proteolytic enzyme, were markedly repressed in response to RU486 treatment in rat ovaries. Also, the down stream pathway of EGF signaling leading to activation of ERK was markedly repressed in RU486 treated ovaries. It was next examined what role the P4/PR system has in the regulation of CL structure and function. Surprisingly, PR expression is absent in CL of rats, while it is present in higher primates. Experiments were carried out to examine intracrine actions of P4 in the regulation of CL structure and function in monkeys. The recently reported model system of induced luteolysis yet capable of responsive to trophic support from the laboratory provided an ideal opportunity to examine direct effects of P4 on structure and function of CL in the monkey. A series of pilot experiments were carried out in monkeys experiencing summer amenorrhea, to determine dose and mode of administration of exogeneous P4 to simulate mid luteal phase circulating P4 concentrations in monkeys subjected to induced luteolysis. Based on the results of pilot experiments, implantation of Alzet pumps containing 97.5mg of P4 was selected for maintaining mid luteal phase P4 concentrations. The microarray data of induced luteolysis previously deposited by the laboratory in NGBI’s gene expression omnibus were mined for identification and validation of differentially expressed genes of PR and its target genes following LH depletion and LH replacement experiments. Expressions of PR, PR cofactors and expressions of PR downstream target genes through out the luteal phase and in CL from day1 of menses were also examined. Analysis of expressions of genes revealed that of the 45 genes identified to be regulated by LH treatment, 4 genes were found to be responsive to P4, and 14 were identified to be responsive to both P4 and LH. Morphology of CL tissue sections revealed that P4 treatment appeared to have reversed the induced-luteolysis changes. In another experiment, implantation of P4 during late luteal phase (i.e., the period of declining P4 concentrations) for 24h caused changes in expressions of genes associated with tissue remodeling and morphology of luteal cells. Taken together, the results suggest that induced luteolysis plus P4 replacement model is suitable for assessing the effects of P4 on CL function. The results also suggest that CL could serve as target tissue for examining the genomic and non genomic actions of P4. In summary, studies carried out in the present thesis provides a comprehensive endocrine hormone profile throughout the menstrual cycle of the bonnet monkey with special emphasis on time course of INH A and FSH secretion which is very useful for future investigations. Studies have been carried out in rats and monkeys with different experimental model systems to address molecular mechanisms underlying inhibin-α regulation in the ovary in general and CL in particular. Experimental findings in monkeys could help elucidate the underlying molecular nature of CL functionality and extrapolate to understand luteal insufficiency and infertility producing conditions in humans. Also different model systems have been validated to examine the actions of P4/PR system in rats and monkeys and more importantly to address the direct effects of P4 upon monkey CL structure and function were established. Future investigations based on findings of these studies should help clarify relative roles for LH and P4 during maintenance of CL function and luteolysis.

Contexte : Les parabènes sont des substances antibactériennes et antifongiques utilisées comme conservateurs dans de nombreux produits d’usage courant (cosmétiques, soins personnels, pharmaceutiques et alimentaires). Des études in vitro et in vivo ont signalé les effets de perturbation endocrinienne des parabènes, soulevant des inquiétudes quant à leurs risques potentiels pour la santé humaine. Objectif : Évaluer l’association entre les concentrations urinaires de parabènes et les concentrations sériques d’hormones de la reproduction (estradiol, progestérone, hormone folliculostimulante et hormone lutéinisante) chez les jeunes filles de la population générale canadienne. Méthodes: Les données de l'Enquête canadienne sur les mesures de la santé (2014 – 2015) concernant les filles âgées entre 6 et 17 ans ont été utilisées pour cette étude. L’association entre les concentrations urinaires de parabènes et des hormones a été analysée par régression linéaire multivariée, en ajustant pour les covariables suivantes : âge, indice de masse corporelle, ethnicité, revenu, et saison lors de la collecte des échantillons urinaires et sanguins. Résultats : Les 382 participantes incluses dans cette étude étaient majoritairement blanches (76%), avaient un indice de masse corporelle normal (73%) et des niveaux détectables d’au moins un parabène (92 %). Des concentrations de parabènes plus élevées étaient associées à des concentrations d'hormones de la reproduction significativement inférieures pour l’estradiol, et les hormones folliculostimulante et lutéinisante; il n’y avait pas d’association pour la progestérone. Un doublement des concentrations des parabènes urinaires était associé à des concentrations inférieures d'estradiol de 5,8% (IC à 95% -9,3; -2,1), d’hormone folliculostimulante inférieure de 4,2% (IC à 95% -7,9; -0,3) et d’hormone lutéinisante inférieure de 10,8% (IC à 95% -17,4; -3,7). Discussion : Cette étude montre que l'exposition aux parabènes était associée à des concentrations circulantes plus faibles d'hormones de la reproduction chez des jeunes filles de la population générale. Le devis transversal ne permet pas de réaliser d’inférences causales. Néanmoins, ces résultats concordent avec les études animales et suggèrent que l’exposition aux parabènes pendant le développement puisse altérer le fonctionnement du système reproducteur. Des études longitudinales permettraient de confirmer, ou non, ces résultats. / Background: Parabens are chemical substances used as preservatives for their antibacterial and antifungal properties in many everyday products (personal care, cosmetics, pharmaceutical and food). Several in vitro and in vivo studies have shown their endocrine disrupting potential, raising some concerns for potential adverse human health effects. Objective: To assess the cross-sectional association between urinary concentration of parabens and serum reproductive hormones (estradiol, progesterone, follicle stimulating hormone and luteinizing hormone) in girls in the general Canadian population. Methods: Data from the Canadian Health Measures Survey (2014 – 2015) on girls aged 6-17 were used for this study. Associations between hormones and parabens were analyzed with multivariable linear regressions, adjusting for potential confounders (i.e., age, body mass index, ethnicity, household income, and sampling season). Results: The girls and teens included in the study (n=382) were mostly white (76%), had a normal body mass index (73%), and detectable levels of at least one paraben (92%). We observed significantly lower concentrations of reproductive hormones with higher paraben concentrations; there was no association with progesterone concentrations. A doubling in urinary parabens was associated with lower estradiol by 5.8% (95% CI -9.3, -2.1), lower FSH by 4.2% (95% CI -7.9, -0.3), and lower LH by 10.8% (95% CI -17.4, -3.7). Discussion: This study shows that exposure to parabens is associated with lower circulating levels of reproductive hormones in young girls in the general population. The cross-sectional design does not allow to make causal inferences. However, these results are consistent with animal studies and suggest that exposure to parabens during development may affect the functioning of the reproductive system. Future studies should employ a longitudinal design verify these results.

Einfluss des Wachstumsfaktors Insulin-like growth factor-I (IGF-I) auf das Follikelwachstum beim Weißbüschelaffen (Callithrix jacchus) Aus dem Veterinär-Physiologisch-Chemischen Institut der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im September 2010 (86 S., 16 Abb., 9 Tab., 225 Lit., 4 S. Anhang) Schlüsselwörter: Insulin-like Growth Factor-I (IGF-I), Granulosazellen, Steroidhormone (Östradiol, Progesteron), Gonadotropine (FSH, hCG) In der vorliegenden Studie wurde die Rolle von IGF-I und das Zusammenwirken mit den Gonadotropinen (FSH, hCG) auf die Sekretion der Steroidhormone (Progesteron, Östradiol) kultivierter Granulosazellen von 13 Weißbüschelaffen untersucht, um zu prüfen, ob und wie weit IGF-I die Sekretion und Reifung der Granulosazellen beeinflusst. Für die in vitro-Experimente wurden Zellkulturen mit Granulosazellen kleiner ( 0,5 - 1 mm) und präovulatorischer Follikel ( > 2 mm) von Ovarien am 7. Tag der Follikelphase verwendet. Vor jedem Versuch wurde das Wachstum der Follikel durch zwei Ultraschalluntersuchungen kontrolliert. Während der Kultur wurden drei Inkubationsintervalle von je 48 h durchgeführt. Die Zellen wurden mit IGF-I allein oder in Kombination mit FSH bzw. hCG stimuliert. Zum Teil wurden die Gonadotropine auch zur Prästimulation verwendet. Das Signifikanzniveau der Hormoneffekte lag bei p<0,05. Bei den Granulosazellen kleiner Follikel lässt sich durch die alleinige Gabe von IGF-I nur am Ende der Kultur (144 h) eine signifikante Erhöhung der Progesteronsekretion feststellen. Bei einer Kombinationsgabe von IGF-I und FSH findet sich schon am Anfang (48 h) ein signifikanter Einfluss auf die Sekretion von Progesteron und Östradiol. Bei der Progesteronsekretion ist der Effekt der Kombination signifikant höher als bei Einzelgabe beider Hormone. Dagegen ist bei der Östradiolsekretion der Effekt der Kombination zwar nicht höher als bei einer alleinigen Gabe von FSH, aber die Zellen reagieren wesentlich schneller auf IGF-I, wenn sie zusammen mit FSH stimuliert werden. Keine signifikante Wirkung in der Steroidhormonsekretion ruft die Hormonkombination IGF-I und hCG im Vergleich zur alleinigen Gabe der beiden Hormone hervor. Bei dem Vergleich beider Gonadotropine ist eine signifikante Erhöhung der Steroidhormonsekretion nur bei alleiniger Gabe von FSH zu beobachten. Bei den Experimenten mit Prästimulationen (FSH oder hCG) lässt sich nur bei der FSH-Prästimulation mit einer nachfolgenden Kombinationsgabe von hCG und IGF-I eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Dies bedeutet, dass FSH die kleinen Granulosazellen auf die Wirkung von hCG sensibilisiert, wobei IGF-I diesen Vorgang unterstützt. Im Gegensatz zu den kleinen Follikeln lässt sich bei den Granulosazellen der präovulatorischen Follikel ein signifikanter Effekt von verschiedenen Hormonstimulationen schon früh beobachten. Durch alleinige IGF-I-Gabe lässt sich bereits am Anfang der Kultur (48 h) eine signifikante Erhöhung der Steroidhormonsekretion feststellen. Eine Kombinationsgabe von IGF-I und der Gonadotropine (FSH oder hCG) zeigt, dass die Kombination mit FSH zu einer signifikanten Erhöhung beider Steroide im Vergleich zur Kontrolle führt. Dagegen zeigt sich bei einer Kombination von IGF-I und hCG eine signifikante Erhöhung der Steroidhormonsekretion schon ab 48 h sowohl im Vergleich zur Kontrolle als auch zur alleinigen Gabe dieser Hormone. Bei der Untersuchung des Effekts beider Gonadotropine (FSH oder hCG) ist schon ab 48 h ein signifikanter Effekt auf beide Steroidhormone zu erkennen. Beide Gonadotropinprästimulationen (FSH oder hCG) mit nachfolgender Hormonkombination (hCG und IGF-I) führen bei den Granulosazellen der präovulatorischen Follikel zu einer signifikant geringeren Steroidhormonsekretion im Vergleich zur Gabe von hCG und IGF-I ohne Prästimulation. Die Zellen reagieren offenbar in dieser Art und Weise, um eine mögliche übermäßige Steroidgenese, und somit eine pathologische Situation, zu verhindern. Die vorliegende Arbeit zeigt, dass IGF-I bei den kleinen und präovulatorischen Follikeln unterschiedliche Wirkungen hervorruft. Es scheint, dass IGF-I die Sekretion von Progesteron und Östradiol auf unterschiedliche Art und Weise beeinflusst, und dass die Granulosazellen der Weißbüschelaffen erst während der Follikelentwicklung die Fähigkeit erwerben, auf IGFI entsprechend zu reagieren. Die Ergebnisse zeigen weiterhin, dass IGF-I bei den Granulosazellen der kleinen Follikel eine eher unterstützende Rolle für die Gonadotropine spielt, und dass IGF-I mit den Gonadotropinen bei der Reifung und der Differenzierung der Follikel mitwirkt. Möglicherweise spielt IGF-I auch während der Entwicklung und des Wachstums des präovulatorischen Follikels sowie bei der Regulierung der Progesteronsekretion eine Rolle. Die vorliegenden Ergebnisse unterstützen die Hypothese, dass IGF-I zusammen mit hCG die Zelldifferenzierung bei den Granulosazellen der präovulatorischen Follikel fördert. Außerdem kann vermutet werden, dass bei den Granulosazellen der präovulatorischen Follikel IGF-I zusammen mit FSH in unabhängiger Weise wirkt. Abschließend kann gesagt werden, dass ein Zusammenwirken zwischen den Gonadotropinen und IGF-I in Bezug auf die Bildung des präovulatorischen Follikels und die darauffolgende Ovulation existiert, dies gilt es auch bei pathologischen Situationen der Follikelreifung und Ovulation zu berücksichtigen.

(Oberflächen-) Gewässer weltweit sind mit geringen Mengen (ng/L bis wenige µg/L) humaner Pharmazeutika belastet. Diclofenac (DCF; nicht-steroidal, entzündungshemmend) und Metoprolol (MTP; ß-Blocker) gehören entsprechend ihres hohen Verbrauchs zu den am häufigsten gefundenen Substanzen. Deren biologische Aktivität ist nicht auf den Menschen beschränkt. Gut konservierte Enzyme innerhalb der Vertebraten legen Auswirkungen auf Nicht-Zielorganismen wie Fische nahe, die bisher in Langzeituntersuchungen mit umweltrelevanten Konzentrationen unzureichend untersucht wurden. In der vorliegenden Arbeit wurden die physiologischen Effekte von DCF und MTP auf die Nil-Tilapie (Oreochromis niloticus), einem der wichtigsten Aquakulturfische weltweit, untersucht. In vitro konnte anhand primärer Hepatozyten gezeigt werden, dass bereits umweltrelevante Konzentrationen von DCF zu einer erhöhten Genexpression verschiedener Schlüsselenzyme der Detoxifizierung führten. Nach MTP-Exposition waren die Veränderungen weniger eindeutig. Beide Substanzen induzierten die Vitellogenin Genexpression, nur DCF jedoch bereits in umweltrelevanter Konzentration. In vivo wurden in zwei Langzeit-Expositionsversuchen die physiologischen Effekte vom befruchteten Ei bis 80 Tage nach Schlupf in O. niloticus untersucht. Beide Substanzen hatte keinen Einfluss auf Schlupferfolg und Überleben, das Wachstum war nach 80 Tagen nach Schlupf leicht reduziert. Die deutlichsten Auswirkungen waren histopathologische Veränderungen der Kiemen, veränderte Genexpressionen der Gonadotropine und eine erhöhte Expression von Vitellogenin. Die Ergebnisse legen eine stärkere östrogene Aktivität von DCF im Vergleich zu MTP nahe. Zusammenfassend sind die Bedenken gegenüber den Einzelsubstanzen eher gering, negative Auswirkungen auf die Reproduktion und sich verstärkende Effekte bei zeitgleicher Exposition gegenüber DCF und MTP lassen sich jedoch nicht ausschließen und sollten im Weiteren untersucht werden. / Surface waters worldwide are contaminated with low levels (ng/L up to few µg/L) of human pharmaceuticals. Diclofenac (DCF; non-steroidal, anti-inflammatory) and metoprolol (MTP; ß-blocker) are highly consumed and therefore commonly detected. Their biological activity is not restricted to humans. Well conserved enzymes within the vertebrates suggest effects on non-target organisms such as fish, poorly studied in long-term exposure experiments using environmentally relevant concentrations. In the presented work, physiological effects of DCF and MTP on the Nile tilapia (Oreochromis niloticus), an important aquaculture fish species, were studied. Using primary hepatocytes, it was shown in vitro that environmentally relevant concentrations of DCF increased the gene expression of different key enzymes of the detoxification, while MTP exposure had a less clear effect. Both substances induced vitellogenin gene expression, but only after DCF exposure this was significantly elevated already at the environmentally relevant concentration. In vivo, two long-term exposure studies on the physiological effects from the fertilized egg until 80 days post-hatch were evaluated. Both substances did not affect hatching success and survival, while growth was slightly reduced after 80 days post-hatch. Histopathological alterations of the gills, changed gene expression patterns of the gonadotropins and induced vitellogenin gene expression were the most dominant findings. The results indicate a stronger estrogenic mode of action of DCF compared to MTP. Overall, the risk due to a single substance exposure seems to be relatively low but adverse effects on reproduction and additive effects during simultaneous exposure to DCF and MTP cannot be excluded and should be investigated further.

Although the female menopause has been extensively characterized as a well-defined symptomatic state of oestrogen deficiency, which responds relatively well to oestrogen replacement therapy, the symptomatic state of androgen deficiency in men is poorly defined and uncertainty exists whether it responds to testosterone replacement. It has been proposed that hypothalamic-pituitary-testicular (HPT)-axis function (responsible for the production of androgens) and regulation could be viewed as a ‘barometer’ of health status in older men and that potential alterations in HPT-axis function and regulation reflect subclinical and clinical deficits in function and health, which may result in an aged phenotype of human health and disease in older men. The HPT-axis constitutes a well-defined, tractable, clinically-relevant, biological system, which may permit insight into the mechanisms underlying the expression of ageing-related phenotypes of human health and disease. By using a different lens – such as the genetic background; the compensatory responses within the HPT-axis; the syndromes of androgen deficiency; the ethnic background of an individual or the life course trajectory of function and health from conception into older age – to magnify potential dysregulation in the HPT-axis will it be possible to visualize and understand the phenotypic expression of human male ageing as a gradient of functional and health outcomes. This will allow for a better understanding of the physiological mechanics underlying symptomatic expression of dysregulation in the HPT-axis.