Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the Neotropics, the major fishes reproductive stimuli are rainfall, temperature and flood. Environmental changes caused by humans affects reproduction directly. The aim of this study was to compare the differences in reproductive investment of Serrasalmus brandtii (native) and Metynnis maculatus (introduced) and its relationship with hydrologic modification in an area of Lower São Francisco. Bimonthly samples were conducted from December/2013 to August/2012 in the main channel of the river, between Propriá (SE) and Porto Real do Colégio (AL) with gillnets of different mesh. Rainfall, temperature, elevation and river flow data were also obtained. The specimens were measured, weighed and dissected to characterize the stage of gonadal maturation, gonad, liver and coelomic fat weight to calculate the gonadosomatic (GSI), hepatossomatic and coelomic fat index. A portion of the left ovary was dissociated to calculate fish fecundity and measurement of oocytes. Serrasalmus brandtii (109 females and 102 males) showed no significant difference in the sex ratio, however M. maculatus (166 females and 259 males) exhibited 1.5 males for each female (χ ²: 20.3, p<0.05). The asynchrony between the sexes, absence of reproductive peaks and lack of correlation between GSI and environmental characteristics observed in S. brandtii indicate losses coming from hydrologic modification. The new environment does not seems to have been a barrier in synchrony (Spearman 0.72, p<0.05), and reproductive process of M. maculatus. Environmental pressures and competition with introduced species may have resulted in earlier maturation of S. brandtii (female: 105mm, male: 92mm) to compensate the losses in its population. Despite the similarity in oocyte size among the species, the positive correlation between body size and absolute fecundity (Pearson: 0.608, p<0.05), allowed a greater number of oocytes in S. brandtii (U: 398, p<0.05) due to its larger size. Both species have opportunistic strategy, characterized by medium-sized body and high reproductive output, with fractional spawning, small oocytes and high relative fecundity. The high colonizing ability of M. maculatus allied to river flow changes facilitated its establishment. Preventive measures should be taken to minimize their impacts on native fauna. / Na regiao neotropical, os principais estimulos reprodutivos para peixes sao pluviometria, temperatura e cheia dos rios. Modificacoes das caracteristicas ambientais em consequencia das acoes antropicas interferem diretamente na reproducao. O objetivo do presente estudo foi comparar a reproducao de Serrasalmus brandtii (nativa) e Metynnis maculatus (introduzida) e sua relacao com a modificacao hidrologica em uma area do Baixo Sao Francisco. Coletas bimestrais ocorreram de agosto/2012 a dezembro/2013 na calha principal do rio, entre Propria (SE) e Porto Real do Colegio (AL) com redes de espera de distintas malhas. Dados de pluviometria, temperatura, cota e vazao do rio tambem foram obtidos. Os especimes foram medidos, pesados e dissecados para caracterizacao do estadio de maturacao gonadal, peso das gonadas, figado e gordura celomica para calculo do indice gonadossomatico (IGS), hepatossomatico e de gordura celomica. Uma porcao do ovario esquerdo foi dissociada para calculos de fecundidade e medicao de ovocitos. Serrasalmus brandtii (109 femeas e 102 machos) nao apresentou diferenca significativa na razao sexual, diferente de M. maculatus (166 femeas e 259 machos), que apresentou 1.5 machos para cada femea ( Ô2: 20.3; p<0.05). A assincronia entre os sexos, ausencia de picos reprodutivos e falta de correlacao entre IGS e caracteristicas ambientais observada para S. brandtii, indicam prejuizos procedentes da modificacao hidrologica. O novo ambiente parece nao ter sido uma barreira na sincronia (Spearman: 0.72; p<0.05) e no processo reprodutivo de M. maculatus. As pressoes ambientais e a competicao com especies introduzidas podem ter resultado na maturacao precoce de S. brandtii (femea: 105mm; macho: 92mm), devido aos prejuizos a sua populacao. Apesar da semelhanca no tamanho do ovocito entre as especies, a correlacao positiva entre tamanho corporal e fecundidade absoluta (Pearson: 0.608; p<0.05) possibilitou um maior numero de ovocitos para S. brandtii (U: 398; p<0.05), em virtude do seu maior porte. Ambas as especies apresentaram estrategia oportunistica, caracterizada pelo medio porte corporal e alto investimento reprodutivo, com desova parcelada, ovocitos pequenos e fecundidade relativa alta. A alta plasticidade de M. maculatus aliada a modificacao fluvial facilitou seu estabelecimento. Medidas preventivas devem ser adotadas para minimizar seus impactos causados a fauna nativa.

O presente trabalho teve como objetivo estudar a morfologia e fisiologia reprodutiva de Lobotes surinamensis em ambiente natural, reunindo informações que permitam trabalhos aplicados na produção e conservação desta espécie. Machos e fêmeas adultos foram coletados na Baía da Ilha Grande, Rio de Janeiro durante a primavera (outubro-novembro-dezembro), verão (janeiro-fevereiro-março), outono (abril-maio-junho) e inverno (julho-agosto-setembro). Os perfis plasmáticos dos esteroides gonadais, 17&beta;-estradiol (E2), 17-hidroxiprogesterona (17-OHP) e 11-cetotestosterona (11-KT) foram analisados em fêmeas, e a concentração de testosterona (T) e 11-KT nos machos. Análises histológicas das gônadas foram realizadas como uma ferramenta para avaliação morfológica, que foi corroborada com os dados fisiológicos, durante o ciclo reprodutivo. Foram analisadas ainda a expressão gênica hipofisária do fsh&beta; e lh&beta; e a fecundidade relativa pelo número de oócitos desenvolvidos. Durante a primavera e verão, as fêmeas estavam com os ovários desenvolvidos e capazes de desovar, com oócitos vitelogênicos e desenvolvidos, e membrana radiata bem evidente. No outono e inverno, as fêmeas estavam se preparando para o período reprodutivo, com predomínio de ninhos de oogônias e oócitos perinucleolares de uma forma geral. A concentração plasmática de E2 se manteve elevada nas fêmeas durante a primavera em relação ao verão e outono/inverno. O perfil anual deste esteroide nas fêmeas de L. surinamensis pode ser relacionado com o grau de desenvolvimento do folículo ovariano, observado na histologia. Já a concentração plasmática de 11-KT foi inversa ao observado para o E2, com baixa concentração na primavera e tendência à elevação no inverno, corroborando com o papel da 11-KT no crescimento primário dos oócitos. A concentração plasmática de 17-OHP nas fêmeas não apresentou diferenças significativas entre as estações, o que sugere que este não seja o progestágeno ativo em teleósteos, mas sim o precursor do esteroide indutor da maturação final (MIS). Na primavera e no verão, o lh&beta; apresentou expressão maior do que no período outono/inverno em fêmeas, enquanto o fsh&beta; se manteve com níveis de expressão constante durante todas as estações. Nos machos, a análise histológica dos testículos, mostrou que na primavera e no verão, os ductos espermáticos estavam preenchidos com espermatozoides, evidenciando o período de espermiação, já no período outono/inverno houve predominância de cistos de espermatogônias e as células em diferentes estágios de desenvolvimento, o que corresponde a uma fase de maturação inicial, ou seja, preparação para o período reprodutivo. A concentração plasmática de T nos machos se manteve estável ao longo das estações, já a concentração plasmática de 11-KT foi mais elevada na primavera quando comparada ao período outono/inverno. Na primavera e verão, a expressão de lh&beta; foi mais elevada que no período outono/inverno, enquanto de forma similar às fêmeas, os níveis de expressão de fsh&beta; não se alteraram ao longo das estações. As análises de expressão destas gonadotropinas, associadas à concentração dos esteroides gonadais e à morfologia gonadal deixou evidente que o pico do período reprodutivo de L. surinamensis ocorre na primavera, estendendo-se até o verão / The present study aimed to study the morphology and reproductive physiology of Lobotes surinamensis in a natural environment, gathering information that allows applied works in the production and conservation of this species. Adult males and females were collected in the Baía da Ilha Grande, Rio de Janeiro during the spring (October-November-December), summer (January-February-March), autumn (April- May-June) and winter (July-August-September). Plasma profiles of gonadal steroids, 17&beta;-estradiol (E2), 17-hydroxyprogesterone (17-OHP) and 11-ketotestosterone (11-KT) were analyzed in females, and the concentration of testosterone (T) and 11-KT in males. Histological analyzes of the gonads were performed as a tool for morphological evaluation, which was corroborated with the physiological data, during the reproductive cycle. The genetic expression of fsh&beta; and lh&beta; and the relative fecundity by the number of developed oocytes were also analyzed. During spring and summer, the females had the ovaries developed and capable of spawning, with vitellogenic and developed oocytes, and a well evident radiata zone. In autumn and winter, females were preparing for the reproductive period, with a predominance of nest of oogonia and perinucleolar oocytes in general. The plasma concentration of E2 remained higher in females during the spring in relation to summer and autumn/winter. The annual profile of this steroid in L. surinamensis females may be related to the degree of development of the ovarian follicle observed in histology. The plasma concentration of 11-KT was inversely of that observed for E2, with a low concentration in the spring and a tendency to increase in winter/autumn, corroborating the role of 11-KT in the primary oocyte growth. The plasma concentration of 17-OHP in the females did not present significant differences between the seasons, suggesting that this is not the active progestogen in teleosts, but the precursor of the final maturation inducing steroid (MIS). In spring and summer, lh&beta; presented higher gene expression than in the autumn/winter period in females, while fsh&beta; remained with constant expression levels during all seasons. In males, the histological analysis of the testicles showed that in the spring and summer, the sperm ducts were filled with spermatozoa, evidencing the period of spermiation, whereas in the autumn/winter period there was a predominance of cysts of spermatogonia and cells in different stages of. development, which corresponds to an initial maturation stage, that is, the preparation for the reproductive period. The plasma concentration of T in males remained stable throughout the seasons, whereas the plasma concentration of 11-KT was higher in the spring when compared to the autumn/winter period. In spring and summer, the expression of lh&beta; was higher than in the autumn/winter period, while similarly to females, fsh&beta; expression levels did not change over the seasons. The analysis of the expression of these gonadotropin genes, associated with the concentration of gonadal steroids and gonadal morphology, made it evident that the peak of the reproductive period of L. surinamensis occurs in the spring, extending until the summer

Em sete adolescentes com dermatomiosite (DM) juvenil (DMJ) foi avaliada a função gonadal através do estadiamento puberal, aspectos da sexualidade, exame físico da genitália e exames complementares: análise seminal (duas amostras com intervalo de um mês), anticorpos anti-espermatozóides, ultra-sonografia escrotal e dosagens hormonais (testosterona, hormônio estimulante do folículo, hormônio luteinizante, prolactina, T3, T4, T4 livre e TSH). Todos os pacientes apresentaram terazospermia, dois tiveram varicocele e um anticorpo anti-espermatozóide localizado em peça intermediária. A futura fertilidade destes pacientes é incerta e estudos de prevalência de função gonadal em populações de jovens e adultos do sexo masculino com DM são necessários / In seven adolescents with dermatomyositis (MD) juvenile (JDM), gonadal function was evaluated through the puberal estadiamento, aspects of the sexuality, examination of the genitalia, semen analysis (two semen samples over a period of one month), anti-sperm, testicular ultrasound and hormones (testosterone, follicle stimulating hormone, luteinizing hormone, prolactin, T3, T4, free T4 and TSH).

Resumo: O lambari Astyanax altiparanae Garutti e Britski (2000) vem ganhando a atenção de pesquisadores e produtores, devido a sua alta taxa de sobrevivência, rápido crescimento, fácil aceitação de alimento artificial, carne saborosa e grande procura como isca viva. As fêmeas apresentam taxas de crescimento mais elevadas do que os machos tornando sua criação mais vantajosa. O processo de diferenciação sexual pode ser controlado pela administração de hormônios sexuais, em peixes sexualmente indiferenciados, alterando o curso da diferenciação no sentido do sexo desejado. Neste trabalho, o desenvolvimento gonadal foi acompanhado nas primeiras 180 horas pós eclosão - hpe (7,5 dias pós eclosão - dpe) das larvas, na tentativa de se conhecer o momento da diferenciação sexual e/ou a melhor fase para aplicação de hormônio feminizante. Foram mantidas 1.000 larvas recémeclodidas em tanques de incubadoras sob aeração constante e temperatura ambiente. Dez exemplares foram diariamente fixados em solução Karnovsky modificada, incluídos em historesina, e corados com HE. Os resultados revelaram que as 12 hpe, o cordão gonadal já está alocado permanecendo por todo o período estudado. Durante o período inicial de aproximadamente 206ºC dias de vida da larva não observou-se, por meio de análise histológica, diferenciação sexual em A. altiparanae. Nesta fase foi possível observar, a abertura da boca que se deu às 19 hpe e a transição alimentar que ocorreu entre 43 e 60 hpe. Em um segundo estudo, a produção de lotes monossexos femininos do lambari foi avaliada, pelo método direto, utilizando o estrógeno, valerato de estradiol, na tentativa de provocar a feminização dos machos. Para isto, foram utilizadas 1.000 larvas de lambari que foram distribuídas em quatro tanques de incubadoras com temperatura média de 21.8 ± 2ºC... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The lambari Astyanax altiparanae Garutti and Britski (2000) has been getting attention of researchers and producers, due to its high rate of survival, fast growth, easy acceptance of food artificial, tasty meat and high demand as live bait. Females have higher growth rates than males making its creation more advantageous. The process of sexual differentiation can be controlled by administration of sex hormones in fish sexually undifferentiated, altering the course of differentiation towards the desired sex. In this study, the gonadal development was observed in the first 180 hours post-hatching - hph (7,5 days post-hatching - dph) of the larvae, in attempt to know the time of sexual differentiation and/or the best stage for the application of female hormone. 1.000 larvae, which were newly-hatched in tanks of incubators under constant aeration and ambient temperature, were kept. Ten specimens were daily fixed in solution Karnovsky modified, included in historesin, and stained with HE. The results showed that 12 hph, the gonadal cord is already allocated by remaining throughout the study period. During the initial period of, approximately, 206ºC-day life of the larva, it is not observed, by means of histological analysis, sexual differentiation in A. altiparanae. At this stage, it was possible to observe the opening of the mouth, which happened at 19 hph, and the food transition, which occurred between 43 and 60 hph. In a second study, the production of female monossex lots of lambari was evaluated by the direct method, using estrogen, estradiol valerate, in an attempt to cause the feminization of males. For this purpose, 1.000 lambari larvae, which had been distributed in four tanks of incubators, in an average temperature of 21.8 ± 2ºC, were used. Initially, the larvae were fed by nauplii of Artemia salina and, 72 hph, their food was replaced by a diet containing 35% crude protein... (Complete abstract click electronic access below) / Orientador: Patricia Pasquali Parise Maltempi / Coorientador: Carmem Silvia Fontanetti Christofoletti / Banca: Rosicleire Veríssimo Silveira / Banca: Yara Aiko Tabata / Mestre

Em sete adolescentes com dermatomiosite (DM) juvenil (DMJ) foi avaliada a função gonadal através do estadiamento puberal, aspectos da sexualidade, exame físico da genitália e exames complementares: análise seminal (duas amostras com intervalo de um mês), anticorpos anti-espermatozóides, ultra-sonografia escrotal e dosagens hormonais (testosterona, hormônio estimulante do folículo, hormônio luteinizante, prolactina, T3, T4, T4 livre e TSH). Todos os pacientes apresentaram terazospermia, dois tiveram varicocele e um anticorpo anti-espermatozóide localizado em peça intermediária. A futura fertilidade destes pacientes é incerta e estudos de prevalência de função gonadal em populações de jovens e adultos do sexo masculino com DM são necessários / In seven adolescents with dermatomyositis (MD) juvenile (JDM), gonadal function was evaluated through the puberal estadiamento, aspects of the sexuality, examination of the genitalia, semen analysis (two semen samples over a period of one month), anti-sperm, testicular ultrasound and hormones (testosterone, follicle stimulating hormone, luteinizing hormone, prolactin, T3, T4, free T4 and TSH).

A espécie em estudo (Brycon orbignyanus) vem apresentando um declínio populacional importante nos últimos anos em função de interferências antrópicas. Por este motivo, populações naturais na bacia do rio Uruguai são praticamente inexistentes, e os estoques mantidos em cativeiro apresentam razões sexuais desproporcionais e perdas importantes de variabilidade genética, o que prejudica o uso desta espécie em programas de conservação. Esta tese tem como objetivo principal avaliar parâmetros populacionais e reprodutivos de Brycon orbignyanus sob condições de cativeiro visando a aplicabilidade deste conhecimento em programas de conservação. Com isso, objetivou-se no primeiro experimento avaliar as flutuações na razão sexual ao longo do desenvolvimento ontogenético e os diferentes padrões morfológicos de crescimento entre os sexos. Quinhentos exemplares foram amostrados de uma piscicultura comercial e os dados biométricos foram registrados para a realização de uma regressão linear entre peso e comprimento. A partir do teste Qui-Quadrado (χ²) foi possível observar que a razão sexual apresentou desproporções nas classes de comprimento superiores. Os machos e fêmeas apresentaram crescimento alométrico positivo (b=3,35 e b=3,44), enquanto indivíduos sexualmente indiferenciados apresentaram alometria negativa (b=2,96) O objetivo do segundo estudo foi descrever os processos de diferenciação sexual, afim de definir o período termossensível. Após eutanásia dos animais, as gônadas foram coletadas e fixadas em solução formaldeído tamponado 4%. Os cortes seriados (3μm) foram corados com Azul de Toluidina e analisados por microscopia de luz. Os primeiros sinais de diferenciação sexual foram observados apenas aos 323 dias após a fertilização (DAF) e, aos 730 DAF todos os indivíduos já estavam diferenciados sexualmente. O objetivo do terceiro estudo foi descrever o ciclo reprodutivo de machos de B. orbignyanus, a fim de se estabelecer uma escala de maturação para machos desta espécie. Para isto, exemplares da espécie foram coletados periodicamente em uma estação de piscicultura comercial. Assim como no experimento anterior, as gônadas foram coletadas e fixadas para análise histológica. As análises das imagens foram obtidas através de microscópio óptico e a descrição das fases reprodutivas seguiu recomendações de Brown-Peterson et al. (2011). Foram estabelecidas 5 fases reprodutivas de acordo com as características macroscópicas dos testículos, presença e distribuição das células espermatogênicas e variações no índice gonadossomático. Os primeiros indivíduos aptos à reprodução foram observados aos 435 DAF. / The species under study (Brycon orbignyanus) has undergone a important population decline in the last years due to anthropic interferences. For this reason, natural populations in the Uruguay River basin are practically non-existent, and stocks kept in captivity suffer from disproportionate sex ratios, and significant losses of genetic variability, impairing the use of this species in conservation programs. The main objective of this thesis is to evaluate the population and reproductive parameters of Brycon orbignyanus under captive conditions aiming the applicability of this knowledge in conservation programs. Thus, the objective of the first experiment was to evaluate the fluctuations in sexual ratio along the ontogenetic development and the different morphological patterns of growth between the sexes. Five hundred specimens were sampled from commercial fish farming and biometric data were recorded for a linear regression between weight and length. From the chi-square test (χ²) it was possible to observe that the sex ratio showed disproportions in the upper length classes. Males and females showed positive allometric growth (b = 3.35 and b = 3.44), while sexually undifferentiated individuals showed negative allometry (b = 2.96). The objective of the second experiment was describe the processes of sexual differentiation, in order to define the thermosensitive period After euthanasia of the animals, the gonads were collected and fixed in 4% buffered formaldehyde solution. Serial sections (3 μm) were stained with Toluidine Blue and analyzed by light microscopy. The first signs of sexual differentiation were observed only at 323 days after fertilization (DAF), and at 730 DAF all individuals were already sexually differentiated. The objective of the third experiment was to describe the reproductive cycle of B. orbignyanus males, in order to establish a maturation scale for males of this species. For this, specimens were collected periodically in a commercial fish farm. As in the previous experiment, the gonads were collected and fixed for histological analysis. The images were obtained through an optical microscope and analyzed according to the description of the reproductive phases suggested by Brown-Peterson et al. (2011). Five reproductive phases were established according to macroscopic characteristics of the testes, presence and distribution of spermatogenic cells and variations in the gonadosomatic index. The first individuals able to reproduce were observed at 435 DAF.

Les écosystèmes marins constituent une cible majeure des changements globaux qui affectent de façon pérenne notre planète.Nous nous sommes intéressés à deux de ces changements susceptibles de menacer le milieu marin : le réchauffement climatique par le biais de l’étude de l’effet du stress thermique sur l’expression de ho-1 et la pollution via l’étude de l’impact des métaux lourds à effets perturbateurs endocriniens (le cadmium et le plomb) sur l’axe hypothalamo-hypophyso-gonado-hépatique (HHGH) chez le loup (Dicentrarchus labrax L.).Nos résultats montrent une réponse importante de ho-1 aux stress thermique et chimique dans le foie. Nous avons également démontré une forte accumulation hépatique du Cd, et à un degré moindre du Pb, accompagnée d’une sur-expression du gène mt codant pour les métallothionéines. Des variations dans l’expression de gènes clés le long de l’axe HHGH (arom b, fshß, arom a…) ont été observées après intoxication par les deux métaux sans pour autant induire des effets physiologiques observables.La question se pose de savoir si la synergie des stress physico-chimiques impacte la dynamique et l’état sanitaire des populations marines. / Marine ecosystems are a major target of global changes that continuously affect our planet. In the present study we investigated two of these changes that may threaten the marine environment: global warming, through the study of the effect of heat stress on ho-1 expression and marine pollution through the study of the impact of heavy metals acting as endocrine disruptors (cadmium and lead) on the hypothalamic-pituitary-gonadal-liver (HHGL) axis in the sea bass (Dicentrarchus labrax L.). Our results show an important response of ho-1 to both thermal and chemical stress in the liver. We also demonstrated a high hepatic accumulation of Cd, and to a lesser extent of Pb. This accumulation was correlated with an overexpression of mt gene coding for metallothionein. Changes in the expression of candidate genes (arom b, fshß, arom a…) along the HHGL axis were observed after metal intoxication but no physiological effects were observed.The question then arises to what extent the synergy of physicochemical stressors impacts the dynamics and the welfare of marine species.

<p>Dopamine regulates movement, cognition and the rewarding effects of addictive drugs. Sex differences mediated by gonadal hormones affect each of these processes. An extensive literature suggests that estrogen augments dopaminergic function. Our laboratory found that female rats exhibit increased locomotor stimulation in response to cocaine and greater cocaine-induced dopamine overflow compared to males, sex differences that emerge in early adulthood. Currently, the underlying mechanisms for these differences are poorly understood. I hypothesized that female rats would have more dopamine neurons in midbrain regions and that ovarian hormones would exert trophic effects on dopamine neurons. Immunohistochemical and stereological techniques were used to quantitate the number of cells in the SNpc and VTA of male and female rats and mice to assess: (1) if sex differences in dopamine neuron number exist and when they emerge, (2) how gonadal hormones influence dopaminergic cell number and dopamine-mediated behaviors (3) the role of specific hormone receptors in the effects on cell number (4) the possibility that dopamine neuron number is directly linked to cocaine-stimulated behavior and electrically-stimulated dopamine release and that these responses to cocaine are mediated through gonadal hormone modulation of midbrain dopamine neuron number. I discovered sex differences in midbrain dopamine neuron number; adult female rodents have more neurons in the SNpc and VTA. We also found that gonadectomy in adulthood reduced midbrain dopamine neuron number in females and increased neuron number in males, establishing the trophic effects of estrogen in the intact midbrain and possible suppressive effects of androgens. Treatment with agonists for estrogen receptor subtypes alpha and beta and androgen receptor reversed the effects of gonadectomy on cell number in females and males, respectively. In an effort to bridge cocaine-stimulated behavior and cell number in sham ovariectomized and ovariectomized females, we discovered cocaine-stimulated behavior, dopamine release and SNpc cell density were positively correlated in intact female rats, an effect that is lost with ovariectomy. This dissertation demonstrates that estrogen is critical for the maintenance of dopaminergic cell populations that enhance behavioral responses to psychostimulants in females, thereby contributing to the observed sex differences.</p> / Dissertation

Environmental factors are known to have far reaching effects on nervous system function, and in the adult brain, it is clear that a wide range of environmental stimuli modulate cell proliferation and survival (e.g., neurogenesis). This project investigated whether social stimulation and concomitant changes in gonadal hormones can influence the proliferation of new cells in the adult brain. The adult green treefrog (Hyla cinerea)was used as the model system; studying the courtship behavior of the highly social treefrog affords a direct, quantifiable way to measure the effects of acoustic social cues and hormonal intervention on adult brain cell proliferation. Using immunohistochemistry techiques, endocrinological manipulations, and socially-relevant acoustic stimulus presentations, I report that social cues modulate cell proliferation in the brains of adult male and female H. cinerea. I first mapped the distribution of proliferative areas in the adult treefrog brain using 5-bromo-2′- deoxyuridine (BrdU) labeling. I then exposed naturally-cycling male and female treefrogs to random tones or a recording of a natural H. cinerea chorus for ten days during the breeding season. I found that male and female treefrogs that heard their conspecific chorus exhibited increased brain cell proliferation compared to animals that heard random tones. Moreover, this modulation was region-specific and occurred in those regions which reflected their presumed involvement in reproductive physiology and behavior: the preoptic area (POA) and the infundibular hypothalamus (IF). To determine the involvement of gonadal hormones in cell proliferation with and without social stimulation, I gonadectomized and implanted male and female H. cinerea with blank or steroid-filled implants. After exposing the treefrogs to the same acoustic conditions as above, I discovered that social modulation of adult cell proliferation can occur without the influence of gonadal hormones (i.e., androgens in the male and estrogen in the female). Furthermore, the results revealed that neither hormone was neurotrophic and in fact, chronically-elevated estrogen levels decreased cell proliferation in the female POA and IF. Together, these results indicate that the reception of acoustic social cues increases cell proliferation in brain regions mediating sexual behavior and endocrine regulation; furthermore, this modulation occurs in a sexually-differentiated fashion without gonadal hormone influence. / text

Thesis (Ph. D.)--University of Texas Health Science Center at Houston, School of Public Health, 1988. / Includes bibliographical references (leaves 165-175).