Die vorliegende Arbeit untersucht die Steroidogenese und die Expression Leydig-Zellspezifischer Gene in Kulturen postnataler fetaler Leydig-Zellen (PFLC). Die Stimulation von PFLC mit hCG und (Bu)2cAMP bewirkt eine Steigerung der Testosteronproduktion in vitro. Es wurde eine zeitabhängige Abschwächung der Testosteronproduktion durch (Bu)2cAMPstimulierte PFLC beobachtet. Diese war begleitet von einer Akkumulation von Progesteron im Kulturmedium und einer Suppression der Expression von P450c17 auf dem translatorischen Level. Während der Kultivierung verloren PFLC ihre Fähigkeit der Expression Leydig-Zell-spezifischer Gene (z.B. 3βHSD, P450c17, Insl3). Dieses Phänomen konnte durch Stimulation mit (Bu)2cAMP rückgängig gemacht werden. Außerdem zeigte sich, dass PDGFα allein und in Kombination mit (Bu)2cAMP signifikant die Proliferation der PFLC in vitro stimulierte. Die vorliegende Arbeit deutet darauf hin, dass cAMP-aktivierte Signalkaskaden eine wichtige Rolle in der Regulation von Differenzierung und Funktion von PFLC spielen.

Thesis (M.S.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Embargoed. Vita. Bibliography: 33-36.

Orientadores: Luis Antonio Violin Pereira, Suzana de Fatima Paccola Mesquita / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-06T21:14:15Z (GMT). No. of bitstreams: 1 Garcia_PatrickVianna_M.pdf: 2397318 bytes, checksum: 8b518ea012a3a11e92ce5775536bee0f (MD5) Previous issue date: 2006 / Resumo: O epidídimo de mamíferos, através da secreção de proteínas andrógeno-dependentes, é responsável pela maturação dos espermatozóides visando o processo de fecundação, alterando-os em características morfológicas e bioquímicas. O criptorquidismo é uma condição patológica congênita na qual os testículos e epidídimos permanecem alojados na cavidade abdominal do organismo, causando a interrupção da espermatogênese e a ausência de espermatozóides no epidídimo, bem como atrofia e alterações histológicas que comprometem a função do epitélio germinativo do testículo e do epitélio secretor do epidídimo. A orquidopexia consiste no posicionamento dos testículos e epidídimos à topologia normal, contudo há ainda relatos de casos de infertilidade pós-orquidopexia. Alterações no epidídimo não revertidas pela orquidopexia poderiam ser co-responsabilizadas pelo baixo índice de fertilidade em indivíduos pós-orquidopexia. O objetivo deste estudo foi descrever em camundongos C57BL/6 as alterações histológicas e estereológicas causadas pelo criptorquidismo experimental e a possível reversibilidade destas alterações pela orquidopexia. Adicionalmente, foram determinadas e comparadas as concentrações séricas de testosterona e o número e o volume do núcleo das células de Leydig em camundongos controles, submetidos à condição de criptorquidismo experimental e à orquidopexia. A condição criptorquídica causou reduções significativas nos parâmetros estereológicos avaliados, contudo as alterações epididimárias foram menos acentuadas do que as verificadas para testículos. Após a orquidopexia, os valores de todos os parâmetros no epidídimo atingiram valores significativamente semelhantes aos controles. A dosagem sérica de testosterona não foi significativamente diferente em nenhum grupo analisado. A persistência da redução no número de células de Leydig na condição criptorquídica associada à não variação dos níveis de testosterona sugerem um mecanismo compensatório da atividade das células de Leydig. Os resultados demonstram que as alterações epididimárias causadas pelo criptorquidismo podem ser revertidas pela orquidopexia. Assim, a orquidopexia pode ser considerada um método eficaz para restauração da espermatogênese e alterações histológicas da cabeça do epidídimo causadas pelo criptorquidismo e, desta forma, sugere-se que a infertilidade, pós-orquidopexia, não deve ser correlacionada às alterações sofridas pela cabeça do epidídimo / Abstract: The mammalian epididymis, through secretion of androgen-dependents proteins, is responsible for maturation of the sperm aiming fecundation process, modifying the sperm in theirs morphological and biochemical features. Cryptorchidism is a pathological condition in which testis and epididymis are retained in the abdominal cavity, resulting in interruption of the spermatogenesis and absence of sperm in the epididymis as well as atrophy and histological alterations that compromise the function of germinative epithelium of the testicle and secretor epithelium of epididymis. Orquidopexy restored the normal topology of testis and epididymis, however there are relates of cases of infertility pos-orchidopexy. Epididymis alterations not reverted by orchidopexy could be coresponsable for decrease fertility potential pos-orchidopexy. The aim of this study was to describe in mice (C57BL/6) by histology and stereological parameters the alterations induced by experimental cryptorchidism in epididymis and testis and the possible reversibility of these alterations by orchidopexy. Additionally were determined and compared serum levels of testosterone, number and nuclear volume of Leydig cells in mice controls and mice submitted to experimental cryptorchidism and orchidopexy. The cryptorchidic conditions caused significantly reduction of stereological parameters that were analyzed, however the epididymal alterations were less decreased than testicular alterations. After orchidopexy, the values of all parameters in the epididymis were significantly similar to controls. The serum testosterone levels were not significantly different among the groups analyzed. The decreased number and nuclear volume of Leydig cells in cryptorquidic conditions not associated with variations of the serum testosterone levels suggest a compensatory mechanism of the Leydig cells activity. The results showed that alterations in caput of epididymis and interruption of spermatogenesis caused by cryptorchidism can be reverted by orchidopexy, suggesting that the infertility, pos-orchidopexy, does not have to be correlated to the alterations suffered by the caput of the epididymis / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Orientador: Rejane Maira Goes / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-14T18:19:29Z (GMT). No. of bitstreams: 1 Pinto_MariaEtelvina_D.pdf: 7979906 bytes, checksum: 0558bfd8fbc931f0f8dfcc8ad0957763 (MD5) Previous issue date: 2009 / Resumo: O gerbilo da Mongólia (Meriones unguiculatus) tem sido utilizado de maneira crescente em estudos sobre o sistema genital masculino. Alguns aspectos da espermatogênese e o ciclo do epitélio seminífero dessa espécie são conhecidos, mas investigações sobre o desenvolvimento pós-natal do testículo e diferenciação das suas principais populações celulares são incipientes. Assim, o objetivo desse estudo foi avaliar os eventos envolvidos com a diferenciação das células germinativas e de Leydig durante o desenvolvimento pós-natal, estabelecer o período de maturação testicular, e descrever a dinâmica das populações de células de Leydig do nascimento à senilidade. Foram utilizados gerbilos machos com 1-6 dias, 1-8 semanas, 3 e 18 meses de idade. Os diferentes tipos celulares foram identificados com base em microscopia de luz de alta resolução, microscopia eletrônica de transmissão e imunocitoquímica para marcadores específicos da linhagem germinativa (VASA) e das células de Leydig adultas (enzimas 3ß-hidroxiesteróide desidrogenase - 3ß-HSD e 11ß-hidroxiesteróide esteróide desidrogenase 1- 11ß-HSD1). Reações imunocitoquímicas para o receptor de andrógeno (AR), para o marcador de células em proliferação (PCNA) e técnica para marcação de células apoptóticas (TUNEL), bem como análises estereológicas dos componentes testiculares e determinação dos níveis séricos de testosterona e estrógeno também foram efetuadas. O processo de migração dos gonócitos para a membrana basal no gerbilo se estende até a segunda semana pós-natal, sendo seguido da sua rápida diferenciação em proespermatogonias. Diferentemente de outros roedores, os eventos relativos à maturação dos gonócitos e sua diferenciação em células da linhagem espermatogonial é mais longo, ocorrem assincronicamente entre os cordões seminíferos e estão associados à perda de sensibilidade ao andrógeno. O desenvolvimento da população de células de Leydig adultas (CLA) envolve quatro estágios progressivos de maturação: as células de Leydig adultas progenitoras, as recém-formadas, as imaturas e as maduras, as quais surgiram, respectivamente com duas, quatro, cinco e seis semanas de idade. As células de Leydig adultas maduras exibem núcleo excêntrico e irregular e um canalículo citoplasmático perinuclear. Também apresentam heterogeneidade funcional em relação à expressão do AR e da enzima 11ß-HSD1. As mudanças que ocorrem no insterstício testicular do gerbilo durante o desenvolvimento pós-natal são muito similares às encontradas em outros roedores, no entanto, o número de células de Leydig fetais permanece constante até a senilidade. Adicionalmente, o surgimento e aumento da população de células de Leydig adultas ocorrem mais tardiamente em relação a outros roedores. A análise histológica indicou que a maturidade testicular no gerbilo ocorre por volta da décima segunda semana de idade. Os níveis séricos de testosterona aumentaram expressivamente a partir da sexta semana de idade, enquanto os de estrógeno permaneceram constantes até a décima segunda semana de idade. Nos animais senis houve uma queda acentuada de ambos os hormônios. O comprometimento da síntese de esteróides nesse último período decorre do prejuízo funcional das CLA. O presente estudo fornece um panorama abrangente do desenvolvimento testicular do gerbilo da Mongólia, ampliando o conhecimento sobre a biologia reprodutiva dessa espécie e proporcionado os fundamentos para o desenvolvimento de estudos experimentais. / Abstract: The Mongolian gerbil (Meriones unguiculatus) has been increasingly used with studies on the male genital system. Some aspects of spermatogenesis and the seminiferous epithelium cycle of this species are known, but investigations about the postnatal development of testis and differentiation of the main cell populations are incipient. The objective of this study was to evaluate the events involved in differentiation of germ cells and Leydig cells during postnatal development, establish the period of testicular maturation, and describe the dynamics of Leydig cells population from birth to senility. Male gerbils were used with 1-6 days, 1-8 weeks, 3 and 18 months of age. The different cell types were identified based on light microscopy, high-resolution transmission electron microscopy and immunocytochemistry for specific markers of germ line (VASA) and adult Leydig cells (enzyme 3 ß-hydroxysteroid dehydrogenase - 3 ß-HSD and 11 ß- hydroxysteroid steroid dehydrogenase 1 - 11 ß-HSD1). Reactions observed for the androgen receptor (AR), for cell proliferation marker (PCNA), technique for marking apoptotic cells (TUNEL), stereological analysis of testicular components and determination of serum levels of testosterone and estrogen were also made. The process of gonocytes migration to the basement membrane in the gerbil extends to the second postnatal week, being followed by their rapid differentiation to proespermatogonia. Unlike other rodents, the events on the gonocytes maturation and differentiation into espermatogonial cell lineage are longer, occur asynchronously between the seminiferous cords and are associated with loss of sensitivity to androgen. The development of the adult Leydig cells (ALC) population involves four progressive stages of maturation: the adult Leydig cell progenitor, newly formed, immature and mature, which appeared respectively with two, four, five and six weeks of age. Mature ALC exhibit irregular and eccentric nuclei and a perinuclear cytoplasmic canaliculus. Also present functional heterogeneity in expression of AR and the enzyme 11 ß-HSD1. The changes occurring in gerbil testicular insterstitium during postnatal development are very similar to those found in other rodents, however, the number of fetal Leydig cells remains constant until senility. Additionally, the emergence and increase of ALC population occur later in relation to other rodents. Histological analysis indicated that the testicular maturity in the gerbil occurs around the twelfth week of age. Serum levels of testosterone significantly increased from the sixth week of age, while the estrogen remained constant until the twelfth week of age. In senile animals there were a sharp fall of both hormones. The impairment of the steroid synthesis in this last period comes from the functional injury of the CLA. This study provides a comprehensive overview of the testicular development of the Mongolian gerbil, expanding knowledge about the reproductive biology of this species and providing the foundation for the development of experimental studies. / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

Philosophiae Doctor - PhD / The metabolic syndrome (MetS) is a collection of various metabolic, hormonal and immunological risk factors that cluster together, closely related to poorly understood phenomena such a hyperinsulinaemia (insulin resistance), hyperleptinaemia (leptin resistance), a low grade, systemic and chronic inflammation and, in males, hypogonadism. Infertility is increasing globally, and male factor infertility accounts for a large percentage of couples who are not able to conceive. The relationship between components of MetS and male reproductive health is not clear, and requires further investigation, as does the impact of MetS on male reproductive health in a case controlled study. The impact of hyperinsulinaemia, hyperleptinaemia and inflammatory cytokines on the male reproductive tract also requires investigation. Furthermore, it is hypothesised that these phenomena negatively impact steroidogenesis cascades. In order to investigate this, a case controlled study and TM3 Leydig cell culture experiments were designed.Participants were recruited from public advertisements, and screened for strict exclusion criteria, including acute or chronic inflammation, hormonal treatments, vasectomy and leukocytospermia (> 106/ml). Following clinical diagnostics, 78 males were either placed into a control group (CG) or the MetS group, with numerous parameters compared between them. Serum was assayed for routine risk markers including HDL cholesterol, triglycerides, glucose and C-reactive protein (CRP). Saliva was assayed for free testosterone and progesterone. Semen samples underwent semen analysis for ejaculation volume, sperm concentration and motility, vitality, morphology and leukocyte concentration, in addition to mitochondrial membrane potential (MMP) and DNA fragmentation (DF). Both serum and seminal fluid were further assayed for insulin, leptin, tumour necrosis factor-alpha (TNF ) and interleukins 1-beta (IL1 ), 6 (IL6) and 8 (IL8). Glucose was also assayed in seminal fluid. Separately, hCG stimulated TM3 Leydig cells were exposed to varying concentrations of insulin (0.01, 0.1, 1 & 10 pg/ml), TNF , IL1 , IL6 and IL8 (0.1, 1, 10 & 100 pg/ml) for 48 hours at optimal cell culture conditions. TM3 cell viability, protein concentration and testosterone and progesterone concentrations were assessed.XXII Results indicated that males in the MetS group (n=34) had significantly increased body mass index, waist circumference, blood pressure, triglycerides, glucose, and Creactive protein (CRP) with decreased HDL cholesterol, as compared to the CG. Furthermore, ejaculation volume, sperm concentration, total sperm count, progressive and total motility were significantly decreased in the MetS group, and sperm with abnormal MMP and DF were increased in this group. No difference was found for morphology. Serum and seminal insulin, leptin, TNF , IL1 , IL6 and IL8 were all significantly increased in the MetS group. Both testosterone and progesterone were also significantly decreased in the MetS group. Insulin increased testosterone and decreased progesterone in the TM3 cells. TNF , IL1 and IL6 all decreased testosterone and progesterone concentrations and TM3 cell viability. IL8 increased TM3 cell viability and decreased progesterone, will no effect on testosterone. These results suggest MetS is associated with decreased fertility potential in males. Furthermore, a significant increase in seminal insulin, leptin, TNF , IL1 , IL6 and IL8 suggests local reproductive tract inflammation in the absence of leukocytospermia. Strong correlations between serum and seminal insulin, leptin, TNF , IL1 , IL6 and IL8, as well as serum CRP, imply that these systemic phenomenons are related to the reproductive tract changes observed. Therefore, the underlying pathophysiology of MetS negatively affects male reproduction, in addition to general health and wellbeing. A decrease in progesterone and testosterone suggests a collapse in steroidogenesis cascades. Additionally, inflammation, increased leptin and insulin resistance likely contribute to this collapse in steroidogenesis based on TM3 cell culture experiments. These results provide novel avenues for further investigations.

La 1α,25(OH)2 vitamine D3 (1,25-D3) est synthétisée à partir du cholestérol par l'exposition solaire de la peau. Les effets de cette hormone sont médiées par le récepteur de la vitamine D (VDR) dans le noyau et à la membrane plasmique, et avec le récepteur PDIA3 ils médient des effets génomiques et non-génomique. La vitamine D joue un rôle important dans la reproduction, puisque la réduction de la fertilité a été observée chez les rats déficients en vitamine D. L'estradiol (E2) est synthétisé à partir de la testostérone par l'enzyme aromatase (CYP19). L’E2 a des effets génomiques et non génomiques médiée par les récepteurs ESR1, ESR2 et GPER. L’objectif de ce travail a été d’étudier l’effet de l’E2 sur le métabolisme et les voies de signalisation de la vitamine D dans des testicules des rats à différents âges ainsi qu’une perturbation éventuelle initiée par un perturbateur endocrinien à activité estrogénique, le Bisphénol A (BPA). Dans le première axe de travail, trois protocoles expérimental (PE) ont été réalisés, où l’E2 et le BPA ont été administrés: traitement de J15pp à J30pp et euthanasie immédiate à J30 (PE1), traitement de J15 à J30 et euthanasie différée à J75 (PE2) et traitement à l’âge adulte de J60 à J75 et euthanasie immédiate à J75 (PE3). Dans le PE1, le traitement avec l’E2 a diminué l'expression du CYP27A1. L’E2 et le BPA ont diminué l'expression du VDR. Cet effet n'a pas été vérifié dans l'expression de la protéine VDR. Dans le PE2, l’E2 a augmenté l'expression des gènes VDR, PDIA3 et CYP27A1, et l'expression de la protéine VDR et CYP27A1. Les traitements n’ont eu aucun effet dans le PE3, ce qui indique qu’un traitement en période prépubère entraîne à la fois un effet immédiat et différé alors que le traitement à l’âge adulte semble sans effet. Dans le deuxième axe de travail, des effets non-génomiques du BPA ont été étudiés par la technique d’afflux de 45Ca2+ dans les testicules de rat prépubères. Le BPA a stimulé l’afflux de 45Ca2+ de manière un peu pareille avec les effets de l’E2. Cet effet semble ne pas impliquer les récepteurs classiques des estrogènes, mais semble se produire de manière compatible avec l'activation d'un récepteur couplé à la protéine G, comme le GPER. Cet effet se produit par la modulation de la fonction des canaux ioniques, comme des canaux potassiques, TRPV1 et des canaux chlorés. Aussi le BPA module le calcium du stock intracellulaire par l’inhibition de la SERCA et l’activation du récepteur IP3. Également des protéines kinases PKA, PKC, MEK et p38MAPK participent de l’effet du BPA, qui pourrait déclencher un cross talk avec les voies de signalisation nucléaires résultant la médiation des réponses génomiques. Dans le troisième axe de travail, l'expression de certains gènes impliqués dans le métabolisme et la signalisation de 1,25-D3 et E2 a été analysée dans des cellules de Leydig. La 1,25-D3 a diminué l'expression du CYP27A1, un effet qui a également été observé lorsque les cellules étaient co-incubées avec l'E2. L’E2 a diminué l'expression des gènes ESR1 et CYP19. Les deux hormones ont démontré un mécanisme de retours négatifs sur leur métabolisme dans ces cellules. Des effets non génomiques ont été étudiés dans ces cellules, où l’E2 semble avoir un effet inhibiteur tandis que la 1,25-D3 a stimulé l'afflux de 45CA2+. A partir de ces résultats, nous pouvons affirmer que la 1,25-D3, l’E2 et le BPA ont des effets moléculaires importants dans le système reproducteur masculin, par l'expression génique des récepteurs et des enzymes impliqués dans le métabolisme des hormones 1,25-D3 et E2. De plus, les résultats obtenus renforcent la théorie selon laquelle il existe une relation entre les voies de signalisation de la 1,25-D3 et l’E2. Comme la 1,25-D3 et l'E2, le BPA stimule également les effets non-génomiques impliqués dans la signalisation du calcium. / 1α,25-dihydroxyvitamin D3 (1,25-D3), the active form of vitamin D, is synthetized from cholesterol by skin exposure to the sun. This hormone’s actions are mediated by vitamin D receptor (VDR) in the nucleus and in the plasma membrane, resulting in genome actions like gene expression regulation. VDR can also be found in the plasmatic membrane, and together with PDIA3 receptor they mediate 1,25-D3 non-genomic actions. Vitamin D has an important role in reproductive function, since fertility reduction was observed in vitamin D deficient rats, as well as VDR and 1α-hydroxylase deficiency. In these animals, calcium and estrogen supplementation was able to reverse the deleterious effects in reproductive function, indicating that there is a relation between 1,25-D3 and estrogens signalling pathways. Estradiol (E2) is synthetized from testosterone by aromatase enzyme (CYP19). E2 is found in high levels in the male reproductive function, and like 1,25-D3 can induce genomic and non- genomic actions, mediated by ESR1, ESR2 and GPER receptors. Bisphenol A (BPA) is a xenoestrogen utilized in plastic industry, capable of modulating the endocrine system through E2 receptors. The aim of this work was to study metabolism and signaling pathways interactions between 1,25-D3 and E2, as well as BPA influence in testicular cells. In the first line of work, three treatment protocols (TP) were realized, where E2 and BPA were administrated in rats between 15th and 30th days, were a portion of the animals were euthanized at the last day of treatment (TP1) and another portion was kept alive after the treatment until euthanized at adult age with 75 days (TP2). A third animal group also received the same treatments when adults (TP3). In TP1, E2 treatment decreased CYP27A1 gene expression. E2 and BPA decreased VDR gene expression. This effect was not verified in VDR protein expression. In TP2, E2 increased VDR, PDIA3 and CYP27A1 gene expression, and VDR and CYP27A1 protein expression, indicating a compensatory effect over gene expression inhibition in prepubertal age. In TP3, treatments did not change gene expression, indicating that prepubertal age is more susceptible to estrogen exposure. In the second line of work, non-genomic effects of BPA were studied through 45Ca2+ influx in prepubertal rat testis. BPA stimulated 45Ca2+ influx in a similar manner to E2. This effect was independent of classical ERs, consistent with a G protein-coupled receptor mechanism, probably GPER. This effect involves the modulation of ionic channels, such as K+, TRPV1 and Cl- channels. Furthermore, BPA is able to modulate calcium from intracellular storages by inhibiting SERCA and activating IP3 receptor/Ca2+ channels at the endoplasmic reticulum and activate kinase proteins, such as PKA and PKC. The rapid responses of BPA on calcium influx could, in turn, trigger a cross talk by MEK and p38MAPK activation and also mediate genomic responses. In the third line of work, the expression of some genes involved in 1,25-D3 and E2 metabolism and signalling were analysed in Leydig cells. 1,25-D3 decreased CYP27A1 gene expression, an effect that was also observed when cells were coincubated with 1,25-D3 and E2. E2 decreased ESR1 and CYP19 gene expression. Both hormones demonstrated an negative feedback mechanism over their on metabolism in these cells. Non-genomic effects were also studied in these cells, where E2 seems to have an inhibitory effect while 1,25-D3 was able to stimulate calcium influx. From these results we can conclude that 1,25-D3, E2 and BPA have important molecular effects in the male reproductive system, through gene expression control over receptors and enzymes involved in the metabolism of the steroid hormones studied. These results also reinforce the theory that there is a relationship between 1,25-D3 and E2 signalling pathways, as well as 1,25-D3, E2 and BPA also have non-genomic actions in calcium signalling.

Insulin-like 6 immunoreactivity (irINSL6) was detected in Leydig cells of the mouse testis. In the brain, labeled somata were detected mainly in the caudal hypothalamus and midbrain. Double labeling the brainstem sections revealed that irINSL6 somata were 5-hydroxytryptamine (5-HT) positive. The presence of irINSL6 in discrete populations of hypothalamic and brainstem neurons and in Leydig cells of the testis suggests a diverse biological function of this novel peptide.

<p>The vervet monkey, Chlorocebus aethiops, an Old World monkey, has been often used in biomedical research programs (toxicological studies and fertility) because of the inaccessibility of relevant human tissues. Data from nonhuman primates have been a vital component of advances in areas such as infertility, contraception, and other reproductive processes because of the phylogenetic closeness of the primates to humans. The aims and objectives of the study were 1) to describe the gross morphology, histology and ultrastructure of the male reproductive system, 2) to describe and compare the processes of spermatogenesis and spermiogenesis of the vervet monkey to humans and other nonhuman primates, and 3) to evaluate the vervet monkey as a possible experimental model for future human reproductive studies.</p> <p>Twenty-nine adult male vervet monkeys, aged between 5 and 11 years, were used. Gross morphological features of different organs of the reproductive tract were recorded. Light and electron microscopic techniques, and methacrylate sections were used on selected tissues of the reproductive tract. The results showed that the vervet monkey has a male&nbsp / reproductive system similar to many non-human primates studied and man. The epididymis was distinctively subdivided into the caput, corpus, and the caudal regions. No significant differences were observed on the epithelial height of these three regions. Four cell types, apical, principal, and basal cells, and the intraepithelial lymphocytes were observed. The basal cell distribution showed significant differences among three regions of the epididymis (P &le / 0.01). There were numerous phagocytic vesicles found in three regions of the epididymis. The Sertoli cells showed perforated sleeve-like processes which encased elongated and mature spermatids ready for spermiation. The nuclei of the Sertoli cells were found to be multilobed (4 to 5) compared to the less lobular nuclei of the human Sertoli cells (2 to 3). The Leydig cells showed typical features of steroidogenic cells with abundant smooth endoplasmic reticulum, numerous large mitochondria, and few rough endoplasmic reticulum.</p> <p>It was concluded that the gross morphology and structure of the reproductive tract of the vervet monkey has many similarities to humans and other mammals. Secondly, the organization of spermatogenesis is similar to that found in humans, and is commonly known as a helical arrangement. The results further suggest that the vervet monkey could be regarded as suitable model for human male reproductive studies.</p> <p>&nbsp / </p>

<p>The vervet monkey, Chlorocebus aethiops, an Old World monkey, has been often used in biomedical research programs (toxicological studies and fertility) because of the inaccessibility of relevant human tissues. Data from nonhuman primates have been a vital component of advances in areas such as infertility, contraception, and other reproductive processes because of the phylogenetic closeness of the primates to humans. The aims and objectives of the study were 1) to describe the gross morphology, histology and ultrastructure of the male reproductive system, 2) to describe and compare the processes of spermatogenesis and spermiogenesis of the vervet monkey to humans and other nonhuman primates, and 3) to evaluate the vervet monkey as a possible experimental model for future human reproductive studies.</p> <p>Twenty-nine adult male vervet monkeys, aged between 5 and 11 years, were used. Gross morphological features of different organs of the reproductive tract were recorded. Light and electron microscopic techniques, and methacrylate sections were used on selected tissues of the reproductive tract. The results showed that the vervet monkey has a male&nbsp / reproductive system similar to many non-human primates studied and man. The epididymis was distinctively subdivided into the caput, corpus, and the caudal regions. No significant differences were observed on the epithelial height of these three regions. Four cell types, apical, principal, and basal cells, and the intraepithelial lymphocytes were observed. The basal cell distribution showed significant differences among three regions of the epididymis (P &le / 0.01). There were numerous phagocytic vesicles found in three regions of the epididymis. The Sertoli cells showed perforated sleeve-like processes which encased elongated and mature spermatids ready for spermiation. The nuclei of the Sertoli cells were found to be multilobed (4 to 5) compared to the less lobular nuclei of the human Sertoli cells (2 to 3). The Leydig cells showed typical features of steroidogenic cells with abundant smooth endoplasmic reticulum, numerous large mitochondria, and few rough endoplasmic reticulum.</p> <p>It was concluded that the gross morphology and structure of the reproductive tract of the vervet monkey has many similarities to humans and other mammals. Secondly, the organization of spermatogenesis is similar to that found in humans, and is commonly known as a helical arrangement. The results further suggest that the vervet monkey could be regarded as suitable model for human male reproductive studies.</p> <p>&nbsp / </p>

Philosophiae Doctor - PhD / The vervet monkey, Chlorocebus aethiops, an Old World monkey, has been often used in biomedical research programs (toxicological studies and fertility) because of the inaccessibility of relevant human tissues. Data from nonhuman primates have been a vital component of advances in areas such as infertility, contraception, and other reproductive processes because of the phylogenetic closeness of the primates to humans. The aims and objectives of the study were 1) to describe the gross morphology, histology and ultrastructure of the male reproductive system, 2) to describe and compare the processes of spermatogenesis and spermiogenesis of the vervet monkey to humans and other nonhuman primates, and 3) to evaluate the vervet monkey as a possible experimental model for future human reproductive studies. Twenty-nine adult male vervet monkeys, aged between 5 and 11 years, were used. Gross morphological features of different organs of the reproductive tract were recorded. Light and electron microscopic techniques, and methacrylate sections were used on selected tissues of the reproductive tract. The results showed that the vervet monkey has a male reproductive system similar to many non-human primates studied and man. The epididymis was distinctively subdivided into the caput, corpus, and the caudal regions. No significant differences were observed on the epithelial height of these three regions. Four cell types, apical, principal, and basal cells, and the intraepithelial lymphocytes were observed. The basal cell distribution showed significant differences among three regions of the epididymis (P ≤ 0.01). There were numerous phagocytic vesicles found in three regions of the epididymis. The Sertoli cells showed perforated sleeve-like processes which encased elongated and mature spermatids ready for spermiation. The nuclei of the Sertoli cells were found to be multilobed (4 to 5) compared to the less lobular nuclei of the human Sertoli cells (2 to 3). The Leydig cells showed typical features of steroidogenic cells with abundant smooth endoplasmic reticulum, numerous large mitochondria, and few rough endoplasmic reticulum. It was concluded that the gross morphology and structure of the reproductive tract of the vervet monkey has many similarities to humans and other mammals. Secondly, the organization of spermatogenesis is similar to that found in humans, and is commonly known as a helical arrangement. The results further suggest that the vervet monkey could be regarded as suitable model for human male reproductive studies