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Background Infertility has become a global phenomenon and constantly declining sperm count in males in modern world pose a major threat to procreation of humans. Male fertility is critically dependent on proper functioning of testicular Sertoli cells. Defective Sertoli cell proliferation and/or impaired functional maturation may be one of the underlying causes of idiopathic male infertility. Using high-throughput "omics" approach, we found binding sites for homeobox transcription factor MEIS1 on the promoters of several genes up-regulated in pubertal (mature) Sertoli cells, indicating that MEIS1 may be crucial for Sertoli cell-mediated regulation of spermatogenesis at and after puberty. Objective To decipher the role of transcription factor MEIS1 in Sertoli cell maturation and spermatogenesis. Materials and methods Sc-specific Meis1 knockdown (KD) transgenic mice were generated using pronuclear microinjection. Morphometric and histological analysis of the testes from transgenic mice was performed to identify defects in spermatogenesis. Epididymal sperm count and litter size were analyzed to determine the effect of Meis1 knockdown on fertility. Results Sertoli cell (Sc)-specific Meis1 KD led to massive germ cell loss due to apoptosis and impaired spermatogenesis. Unlike normal pubertal Sc, the levels of SOX9 in pubertal Sc of Meis1 KD were significantly high, like immature Sc. A significant reduction in epididymal sperm count was observed in these mice. The mice were found to be infertile or sub-fertile (with reduced litter size), depending on the extent of Meis1 inhibition. Discussion The results of this study demonstrated for the first time, a role of Meis1 in Sc maturation and normal spermatogenic progression. Inhibition of Meis1 in Sc was associated with deregulated spermatogenesis and a consequent decline in fertility of the transgenic mice. Conclusions Our results provided substantial evidence that suboptimal Meis1 expression in Sc may be one of the underlying causes of idiopathic infertility.

Sertoli cells play vital roles in normal spermatogenesis, and microRNAs (miRNAs) participate in regulating Sertoli cell development. However, the functions and mechanisms of action of most identified miRNAs in porcine Sertoli cells remain largely unknown. Herein, we primarily explored the regulatory roles of miR-130a in immature porcine Sertoli cells using EdU-based high-content screening assay. The results demonstrated that 27 miRNAs have potential roles in the promotion of immature porcine Sertoli cell proliferation, and miR-130a was identified as a promising candidate. miR-130a promoted cell cycle progression and cell proliferation, whereas it impeded cell apoptosis in immature porcine Sertoli cells. It also contributed to Sertoli cell proliferation and testis development in vivo. A TMT-based proteomics approach revealed that miR-130a regulated the expression of 91 proteins and multiple pathways, including the TGF-β and PI3K/AKT signaling. miR-130a did not directly target the 3'-UTR of SMAD5; however, it increased SMAD5 phosphorylation. Moreover, miR-130a enhanced TGF-β signaling by activating SMAD5 protein, and TGF-β signaling further activated the PI3K/AKT signaling pathway to promote cell proliferation and inhibit cell apoptosis in porcine immature Sertoli cells. Collectively, miR-130a promoted immature porcine Sertoli cell growth by activating SMAD5 through the TGF-β-PI3K/AKT signaling pathway. This study, therefore, provides novel insights into the effects of miR-130a on porcine spermatogenesis through the regulation of immature Sertoli cell proliferation and apoptosis.

The proliferation and differentiation ability of testicular Sertoli cells directly affects spermatogenesis and male reproductive development. WNT proteins are involved in the regulation of cell proliferation, differentiation and spermatogenesis. Therefore, to study whether lncRNAs, which regulate the expression of WNT proteins during cell proliferation and differentiation, are worthwhile. In this study, testicular tissue from the Dazu black goat (Capra, goat, Chongqing, China) at neonatal time (less than 7 days old), early puberty time (45 days old) and sexual maturity time (90 days old) at three ages was subjected to high-throughput sequencing to predict testicular growth and development associated with WNT lncRNA. The final screening of lncWNT3-IT may be targeted to regulate the expression of WNT3. At the same time, the expression of WNT3 was verified by lncWNT3-IT by paraffin sectioning, fluorescence in situ hybridization, interference, overexpression, cytotoxicity assay, Western blotting and qPCR. The following results were obtained: lncWNT3-IT was expressed in the testicular Sertoli cells and played a role in the Sertoli cell cytoplasm. Fluorescence in situ hybridization localization analysis showed that lncWNT3-IT positively regulated the expression of WNT3, and through cell viability and cell proliferation experiments, it was found that the expression of lncWNT3-IT assisted in Sertoli cell proliferation. In summary, lncWNT3-IT can influence the proliferation of Sertoli cells by positively regulating the expression of WNT3.

Immature Sertoli cell proliferation determines the total number of mature Sertoli cells and further regulates normal spermatogenesis. Accumulating evidence demonstrates that microRNAs (miRNAs) play regulatory roles in immature Sertoli cell proliferation, while the functions and mechanisms of the Sertoli cells of domestic animals are poorly understood. In the present study, we aimed to investigate the roles of miR-362 in cell proliferation and apoptosis of porcine immature Sertoli cells. The results showed that miR-362 inhibition promoted the entrance of cells into the S phase and increased the expressions of cell cycle-related genes c-MYC, CNNE1, CCND1 and CDK4. Knock-down of miR-362 also promoted cell proliferation and inhibited apoptosis, which was demonstrated by the results from cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) and Annexin V-FITC/PI staining assays. The recQ-mediated genome instability protein 1 (RMI1) gene was identified as a potential target gene of miR-362 via luciferase reporter assay, and miR-362 repressed the protein expression of RMI1 in porcine immature Sertoli cells. siRNA-induced RMI1 knock-down further abolished the effects of miR-362 inhibition on porcine immature Sertoli cells. Collectively, we concluded that miR-362 knock-down promotes proliferation and inhibits apoptosis in porcine immature Sertoli cells by targeting the RMI1 gene, which indicates that miR-362 determines the fate of immature Sertoli cells.

As the major somatic cell type, Sertoli cells undergo active proliferation and play essential roles to establish testis cord at fetal stage. They also function to maintain germ cell development throughout the life of testicular development. However, the significance of Sertoli cell number for testis cord development and gonocyte fate is still unclear. Nuclear protein ataxia-telangiectasia (NPAT, also known as p220), a substrate of cyclin E/cyclin-dependent kinase 2, is well known as a regulator of cell proliferation through regulating histone expression. To study the role of NPAT during Sertoli cell development, we generated a mouse strain carrying conditional floxed Npat alleles, when crossing with anti-Mullerian hormone-cre, leading to the specific deletion of Npat in Sertoli cells. Npat disruption in Sertoli cells inhibited the programmed proliferation of fetal Sertoli cells resulting in disruption of developing testis cords, and subsequent postnatal mutant testes were severely hypoplastic. Germ cells, which are presumed to be in quiescent status during perinatal stage, exited G0 phase arrest and re-enter mitotic cell cycle prematurely. Of particular note, some germ cells possessed the meiotic signal in Npat-deficient testes. Our data thus indicates that the function of Npat-dependent Sertoli cells is essential at multiple steps in testis development, and this study also identifies Sertoli cells as a major regulator of germ cell development, which are required to maintain a local growth niche to repress premature mitosis and meiosis of gonocytes.-Jiang, X., Yin, S., Fan, S., Bao, J., Jiao, Y., Ali, A., Iqbal, F., Xu, J., Zhang, Y., Shi, Q. Npat-dependent programmed Sertoli cell proliferation is indispensable for testis cord development and germ cell mitotic arrest.

The correct functioning of Sertoli cells (SCs) is pivotal for successful spermatogenesis. They are major targets for hormones, endocrine disruptors, and other substances that men are subjected to every day. One of the main SC functions that quickly responds to a deleterious stimulus is proliferation. This is directly related to the in vivo capacity of these cells to sustain a good number of developing germ cells. The protocols in this article can be tested on SCs of different origin. For the case of human SCs from small human testicular biopsies, a short and simple protocol to isolate and culture these cells is provided. The other protocols discussed herein represent two different procedures, somewhat complementary, to assess SC proliferation. In brief, the sulforhodamine B assay allows the investigator to dye healthy fixed SCs maintained in culture. In the MTT assay, on the other hand, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) is reduced by live SCs. These methods are mostly used to evaluate how SC proliferative activity responds to exposure to compounds such as toxicants or hormones. © 2019 by John Wiley & Sons, Inc.

Aims To describe four cases of incidentally detected microscopic ovarian hilar Sertoli cell proliferation, a phenomenon that, as far as we are aware, has not been previously reported, and to discuss the differential diagnosis of these lesions. Methods and results The proliferations occurred in women aged 35–62 years, and were composed of solid and hollow tubules that were morphologically and immunohistochemically in keeping with Sertoli cells. Two cases were bilateral. Conclusions We feel that these uncommon proliferations are likely to represent non-neoplastic embryological remnants rather than hilar Sertoli cell tumours.

SUMMARY Mammalian target of rapamycin (mTOR) is known to be involved in mammalian cell proliferation, while S-phase kinase-associated protein 2 (SKP2) plays a vital role in the cell cycle. Within the testis, estrogen also plays an important role in Sertoli cell proliferation, although it is not clear how. The present study asked if mTOR is involved in 17β-estradiol-dependent Sertoli cell proliferation. We specifically assessed if extracellular signal-regulated kinase 1/2 (ERK1/2) and/or phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) exert convergent effects toward the activation of mTOR signaling, and if this signaling regulates the expression of SKP2 through retinoblastoma (RB) and early mitotic inhibitor 1 (EMI1) protein and on CCNE1 and CCND1 mRNA levels. Treatment with 17β-estradiol for 15–90 min activated mTOR, with mTOR phosphorylation peaking after 30 min. U0126 (5 μM), a specific inhibitor of (MEK1/2), and 10-DEBC (2 μM), a selective inhibitor of AKT, both significantly reduced 17β-estradiol-induced phosphorylation of mTOR. Rapamycin suppressed 17β-estradiol-induced Sertoli cell proliferation, appearing to act by reducing the abundance of SKP2, CCND1, and CCNE1 mRNA as well as RB and EMI1 protein. These data indicated that 17β-estradiol enhances Sertoli cell proliferation via mTOR activation, which involves both ERK1/2 and PI3K/AKT signaling. Activated mTOR subsequently increases SKP2 mRNA and protein expression by enhancing the expression of CCND1 and CCNE1, and inhibits SKP2 protein degradation by increasing EMI1 abundance. Mol. Reprod. Dev. 82: 305–314, 2015. © 2015 Wiley Periodicals, Inc.

Nitric oxide (NO) plays crucial roles in several physiological and pathological conditions. The iNOS isoform produces high levels of NO independent of intracellular calcium and, in the testis, which is expressed in Sertoli (SC), Leydig (LC) and germ cells. The testicular roles of NO are unclear, but it can inhibit LC testosterone production. Our aim was to evaluate the effects of iNOS deficiency on testis development in mice from late fetal life through early puberty. Therefore, testes from wild type (C57BCL/6) and iNOS(-/-) mice (B6.129P2- Nos2(tm1Lau) /J) were sampled at various ages between e18.5 and Pnd20 and evaluated by histological and stereological analyses; proliferating cells were labelled with (3)H-thymidine. At all ages, testis weight and anogenital index, a measure of fetal androgen exposure, were greater in iNOS-deficient mice than in wild type mice. At all ages after birth, iNOS-deficient mice exhibited increased (p < 0.05) SC number per testis, and this was accounted for by a higher SC proliferation index (p < 0.05) in iNOS-deficient mice, especially on Pnd1 and Pnd5. Similarly, LC number per testis was higher (p < 0.05) in iNOS(-/-) mice than in wild type at all post-natal ages. Highly positive and significant correlations were observed between the proliferation index for SC, LC and peritubular myoid cells on e18.5 and post-natally. Although lumen formation was slightly advanced in iNOS(-/-) mice, no obvious other effects on pubertal testis development were observed. These results imply that NO may normally constrain testis somatic cell development, especially SC, perhaps by limiting testosterone production. Removal of this constraint results in normal, but larger, testes with greater sperm production. Our data pinpoint the window of iNOS (NO) action on SC proliferation and raise the possibility that experimental manipulation of NO in early post-natal life could be used to enhance SC proliferation if this was deficient for any reason.

In eukaryotes, mRNA is actively exported to the cytoplasm by a family of nuclear RNA export factors (NXF). Four Nxf genes have been identified in the mouse: Nxf1, Nxf2, Nxf3, and Nxf7. Inactivation of Nxf2, a germ cell-specific gene, causes defects in spermatogenesis. Here we report that Nxf3 is expressed exclusively in Sertoli cells of the postnatal testis, in a developmentally regulated manner. Expression of Nxf3 coincides with the cessation of Sertoli cell proliferation and the beginning of their differentiation. Continued expression of Nxf3 in mature Sertoli cells of the adult is spermatogenesis stage-independent. Nxf3 is not essential for spermatogenesis, however, suggesting functional redundancy among Nxf family members. With its unique expression pattern in the testis, the promoter of Nxf3 can be used to drive postnatal Sertoli cell-specific expression of other proteins such as Cre recombinase.

The role of thyroid hormones in testis structure and function has been fairly well studied in laboratory rodents. However, there are no comprehensive data in the literature for mice regarding the effects of transiently induced neonatal hypo- and hyperthyroidism on testis and spermatogonial cell development from birth to adulthood. Our goals were to evaluate the effects of propylthiouracil (PTU) and triidothyronine (T3) on Sertoli cell proliferation/differentiation and to correlate these events with the evolution of the spermatogenic process, tubular lumen formation, blood vessel volume density, and size and number of different spermatogonial types. Although Sertoli cell maturation was accelerated or delayed, respectively, in T3- and PTU-treated mice, the pace of the germ cell maturation was only slightly altered before puberty and the period of Sertoli cell proliferation was apparently not affected by the treatments. However, compared with controls, the total number of Sertoli cells per testis from 10 days of age to adulthood was significantly increased and decreased in PTU- and T3-treated mice, respectively. In comparison to all other spermatogonia, type A(2) was the largest cell in all ages and groups investigated. The PTU-treated mice had a significantly increased total number of undifferentiated spermatogonia as well as volume and percentage of vessels/capillaries, probably due to the higher number of Sertoli cells, particularly at 10 days of age. Taken together, our results suggest that neonatal hypothyroidism may be a valuable tool for studying spermatogonial biology as well as a means for providing more spermatogonial stem cells that could potentially be used for spermatogonial transplantation, thereby optimizing the efficiency of this technique when young mice are used as donors.

Numerous parameters have to be tested to identify optimal conditions for prepubertal testicular tissue banking. Our study evaluated 19 different cryopreservation conditions for immature testicular tissue using a rapid screening method. Immature mice testes were cryopreserved using either 1,2-propanediol (PROH) or dimethyl sulfoxide (DMSO) at a concentration of 0.75 or 1.5 M using a controlled slow-cooling rate protocol with (S+) or without seeding (S+). Equilibration was performed either at room temperature or at 4°C for 15 or 30 minutes. Seminiferous cord cryodamage was determined by scoring morphologic alterations. Cell proliferation ability was evaluated using a proliferating cell nuclear antigen (PCNA) antibody. Testes cryopreserved with optimal conditions were grafted into immunodeficient mice. The highest proportions of PCNA-positive nuclei and lowest morphologic alterations were observed with 1.5 M DMSO. Tissues were more altered with 0.75 M DMSO or PROH. Complete germ cell maturation was observed after allografting of testicular pieces previously frozen with 1.5 M DMSO, S+, 30 minutes. The 1.5 M DMSO, S+ or S+ protocol preserved prepubertal mice testicular tissue architecture and germ cell and Sertoli cell proliferation potential. Allografting of thawed testis fragments into immunodeficient mice confirmed that the 1.5 M DMSO, S+, 30 minutes protocol maintained testicular somatic and germ cell functions. Postthaw histologic evaluation and PCNA immunostaining are useful to rapidly test numerous freeze-thaw parameters. They may also be efficient tools to control human prepubertal frozen testis quality, within the context of a clinical application.

Connexin 43 (CX43, also known as GJA1) is the predominant testicular gap-junction protein. In the seminiferous epithelium, gap junctions occur between adjacent Sertoli cells and between Sertoli and germ cells. The specific role of CX43 in Sertoli cell has been difficult to study because of the neonatal lethality of the Cx43 global knockout. Recently two laboratories have independently developed a Sertoli cell conditional Cx43 knockout using Cre-loxP methodology. These have allowed the role of CX43 in Sertoli cells to be determined while circumventing lethal abnormalities in organs such as the heart seen in Cx43 global knockouts. In this review the focus is on the insights into the role of CX43 in Sertoli cells derived from these new model systems. Results indicate that CX43 is essential for cessation of proliferation and normal maturation in Sertoli cells. In addition, CX43 in Sertoli cells is required for spermatogenesis, but not early germ cell proliferation. These model systems show that CX43 is important in Sertoli cell development, and will be useful in further studies of its role in Sertoli cell and testis biology.

There is strong evidence that thyroid hormones through triiodothyronine (T3) regulate Sertoli cell proliferation and differentiation in the neonatal testis. However, the mechanism(s) by which they are able to control Sertoli cell proliferation is unclear. In the present study in vivo approaches (PTU-induced neonatal hypothyroidism known to affect Sertoli cell proliferation) associated with in vitro experiments on a Sertoli cell line were developed to investigate this question. We demonstrated that the inhibitory effect of T3 on Sertoli cell growth, analyzed by evaluating DNA-incorporated [3H] thymidine, was associated with a time and dose-dependent increase in the levels of Cx43, a constitutive protein of gap junctions, known to participate in the control of cell proliferation and the most predominant Cx in the testis. These Cx43 changes were associated with increased gap junction communication measured by gap FRAP. Consistent with these results two specific inhibitors of gap junction coupling, AGA and oleamide, were able to significantly reverse the T3 inhibitory effect on Sertoli cell proliferation. The present data also revealed a nongenomic effect of T3 on Cx43 Sertoli cells that was evidenced by a rapid up-regulation of gap junction plaque number as identified in Cx43-GFP transfected cells exposed to the hormone. This process appears mediated through actin cytoskeleton since incubation of the cells with cytochalasin D totally reversed the T3 stimulatory effect on Cx43-GFP gap junction plaques. Based on these data, we propose a working hypothesis in which Cx43 could be an intermediate target for T3 inhibition of neonatal Sertoli cell proliferation.

Background: The immunoprotective nature of the testes has prompted numerous investigations into their supportive roles during allogeneic or xenogeneic cellular grafts. However, the optimal developmental stage of these cells in terms of maximum efficacy for cellular grafts has not been elucidated. In this study, the time-dependent expressions of immune-privilege- and proliferation-related molecules in Sertoli cells were determined. Methods: To investigate the time course of the expression of proteins related to immune privilege and proliferation, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) were performed using testes of 18 Yorkshire pigs from birth to 20 weeks of age. We included fas ligand (FasL), transforming growth factor β1 (TGF-β1) and clusterin as the immune-protective molecules, and follicle stimulating hormone receptor (FSHR), p27Kip1, GATA-4 and Wilm's tumor antigen (WT1) as Sertoli cell proliferation markers. RT-PCR was used to complement histological assessment. Results: The expression of FasL in Sertoli cells gradually increased with age, whereas TGF-β1 showed the reverse pattern, and clusterin expression showed no age-related difference. p27Kip1 showed a gradual increase in its expression from week 12, but GATA-4 showed earlier postnatal expression from birth to week 12. WT1 expression gradually increased from week 16. Conclusion: We confirmed the age-dependent expression of immune-privilege- and proliferation-related molecules in porcine Sertoli cells. These data may be useful for determining the optimal time for harvesting Sertoli cells with respect to maximal immunoprotection and proliferative activity.

Testes of hypogonadal (hpg) mice show arrested postnatal development due to congenital deficiencies of gonadotrophin-releasing hormone (GnRH) and gonadotrophin synthesis and secretion. Follicle-stimulating hormone (FSH), androgen or oestrogen treatment restore qualitatively normal spermatogenesis in hpg testes. Understanding the cellular and molecular changes accompanying hormone-induced spermatogenesis in hpg mice requires detailed morphological analyses of the germ cells and Sertoli cells in the untreated hpg testis. We compared seminiferous epithelial cytology in adult hpg, immature and adult wild-type mice using unbiased optical disector-based stereology, immunolocalization of Sertoli cell microtubules (MT), espin (a component of the blood-testis barrier), markers of Sertoli cell maturity (p27(kip1) and WT-1), and electron microscopy. Hpg testes had marked reductions in weight, seminiferous cord volume and length, and severe spermatogenic impairment with germ cells per testis < 1% of adult wild-type testes. Sertoli cell nuclei expressed WT-1 in hpg testes, but often were centrally located, similar to 9-14-day-old wild-type testes, and they expressed p27(kip1), indicating that hpg Sertoli cells were post-mitotic. Hpg testes had significantly (P < 0.05) reduced Sertoli cells per testis (0.56 million) compared with 10-day wild-type (1.15 million) and adult wild-type testes (2.06 million). Immunofluorescence labelling of normal adult Sertoli cells showed supranuclear MT columns and basally located espin, but these features were absent in 10-day-old and hpg Sertoli cells. Hpg Sertoli cells showed pleomorphic nuclear ultrastructure with mature-type nucleoli, similar to normal adult-type Sertoli cells, but hpg Sertoli cells exhibited incomplete tight junctions that lacked ectoplasmic specializations. We conclude that in hpg mice, chronic gonadotrophin insufficiency restrains Sertoli cell proliferation and maturation, forming pseudo-adult-type Sertoli cells that are incapable of supporting germ cell proliferation and maturation.

Sertoli cells from the testis contain immunoprotective properties which allow them to survive as allografts and also to protect islets and adrenal chromafin cells from immune rejection without the use of immunosuppressive drugs. Experiments were designed to determine whether xenogeneic neonatal porcine Sertoli cells (NPSCs) survive transplantation in rats without the use of immunosuppression. NPSCs (92.2 +/- 5.1%) were isolated, cultured and then transplanted under the kidney capsule of non-immunosuppressed Lewis rats. To assess survival, grafts were removed after 4, 20, 30, 40, 60, and 90 days post-transplant and immunostained for the Sertoli cell marker vimentin. Survival was confirmed by polymerase chain reaction (PCR) for the porcine mitochondrial cytochrome oxidase II (COII) subunit gene, a marker for porcine tissue. In both methods, NPSCs were detected in the grafts for at least 90 days. Histologically, NPSCs were clustered in small aggregates or organized in tubule-like structures. When stained for the presence of proliferating cell nuclear antigen (PCNA), many Sertoli cells stained positive at 20 days post-transplant, indicating not only cell survival but also Sertoli cell proliferation. The number of PCNA positive cells decreased somewhat by 40 days with almost no positive Sertoli cells at 60 and 90 days. These data demonstrate that NPSCs survive long-term following xenotransplantation in rats, which to our knowledge is the first report of a discordant xenograft surviving without immunosuppression in a non-immunoprivileged site. Further study of the mechanism of NPSC xenograft survival may provide clues for promoting a local tolerogenic environment.

Young boars were treated with propiothiouracil to induce hypothyroidism to examine its effects on postnatal testicular development. Treatments with 0.1% 4-propyl-2-thiouracil (PTU) in drinking water started after weaning, at 3 weeks of age and all boars were severely hypothyroid at 6 weeks of age as determined by measuring T3 and T4 in blood plasma. Boars were castrated at different ages up to 20 weeks and their testes used for histological and immunohistochemical analyses. Although small but significant reduction in testis weight was observed from 8 to 12 weeks of age, this was not accompanied by significant difference in testicular volume. By 20 weeks of age, at the beginning of puberty, the differences in testis weights between control and treated groups of boars disappeared suggesting there is no lasting effect of hypothyroidism on postnatal development of boar testis. Immunohistochemical staining was used to determine the presence of molecular markers in both Sertoli and Leydig cells. Again, there were no differences between testes from control and treated boars in the pattern or intensity of immunostaining using antibodies against 3beta-hydroxysteroid dehydrogenase, antimullerian hormone or proliferating cell nuclear antigen (PCNA). Immunostaining with antibodies against PCNA showed interesting results as it was observed that Sertoli cells still express this marker of proliferating cells at 14 weeks of age, later than previously suggested cessation of Sertoli cell proliferation. This study suggests that hypothyroidism in boars does not have similar effects on postnatal testis development as reported in some other species.

The effects on testis weight and histopathology were studied in 11-day-old male Wistar rats after prenatal exposure to peanut oil (control), diethylstilboestrol 30 microg/kg b.wt./day, or 4-n-nonylphenol 75 mg/kg b.wt./day from gestational day 11 to 18. Additionally, the diameter and length of seminiferous tubules, and the number of Sertoli cells were investigated with stereological methods. Such unbiased methods have not previously been applied on testis diameter and length or on Sertoli cell number of 11-day-old rats. In the control group, the mean length of the seminiferous tubule was 3.0 m+/-0.6, the mean diameter of the seminiferous tubule was 83 microm+/-6, and the mean number of Sertoli cells was 26.1x10(6)+/-4.6. No differences in testis weight, histopathology, or length or diameter of the seminiferous tubules were observed in the diethylstilboestrol and nonylphenol exposed groups when compared to the control group. In the diethylstilboestrol-treated group, a statistically significant decrease in the number of Sertoli cells was observed (P

Thyroid hormones appear to determine adult testis size in rodents by regulating the period of Sertoli cell proliferation in the neonatal period. In the present study, the correlation between neonatal thyroid hormone levels (T3 and thyroxin, T4) and postpubertal testis size in Simental bulls was examined. T3 and T4 levels were measured in blood plasma from 35 calves immediately after their arrival at the AI centre at age 3-6 months. Testis size (height and width) was measured at 12 months of age in the same live animals. A significant negative correlation (r = -0.55; p < or = 0.001) was found between T4 and calculated testicular volume using either the Pearson correlation test or linear regression analysis, while the levels of T3 and testis volume showed a negative correlation, although this did not reach statistical significance (r = -0.20, p < or = 0.05). The results of this study suggest, therefore, that neonatal thyroid hormone levels might have the same effect on testicular size in cattle as they do in rodents.

BACKGROUND: Exemestane is an irreversible steroidal inhibitor of cytochrome-P450 aromatase required for estrogen synthesis. The safety of the drug in the pediatric population, particularly in males, has not previously been evaluated. Given the increased interest in treating children with aromatase inhibitors, we undertook a study in rats to assess the potential for exemestane to alter reproductive development and function when administered to juveniles. METHODS: Male and female rats were treated with exemestane at doses anticipated to produce exposures approximately 2- and 35-fold the expected clinical plasma exposure in young adult males during the period of reproductive maturation. After maturation, treated rats were mated to evaluate the potential impact on reproductive function. RESULTS AND CONCLUSION: There were no effects on sexual maturation in either sex or on female reproductive function. Treatment of juvenile male rats caused increased cohabitation time and decreased copulation rates; pregnancy rates and litter size were not affected in rats that mated. Decreased testis (10–15%) and epididymis (20–30%) weights, and decreased Sertoli cell numbers were noted at all doses. This indicates that exemestane can reduce Sertoli cell proliferation during maturation. The sensitive window for this effect is expected to be limited to the period of Sertoli cell proliferation, which is completed by around postnatal day 15 in rats and before puberty in humans. Treatment beginning at a later time relative to the window for Sertoli cell proliferation or for a longer duration is not expected to have additional adverse effect as the effect was not shown to be degenerative. Birth Defects Res (Part B) 92:304–313, 2011. © 2011 Wiley-Liss, Inc.

During perinatal development, when the size of the Sertoli cell population is determined, Leydig cells produce beta-endorphin, a peptide which may interact with Sertoli cells to modify their FSH-responsiveness, as suggested by our previous work. The goal of the present study was first, to test directly the possibility that beta-endorphin modifies the proliferative response of neonatal Sertoli cells to FSH, and second, to gain information on a mechanism(s) involved in any observed effect. We treated isolated 6-day-old Sertoli cells with FSH or vehicle in vitro and measured their incorporation of exogenous, radiolabeled thymidine with quantitative autoradiography. After 2 days in culture with FSH, we detected a 10-fold increase in the rate of Sertoli cell proliferation. The level of cell division in these FSH-treated cultures was identical to that in other cultures exposed to cAMP under similar conditions. In addition, inclusion of beta-endorphin 3 hr prior to FSH or cAMP decreased the effect of the hormone by 50% but left the cAMP response unchanged. Thus, beta-endorphin acts on isolated, neonatal Sertoli cells at a point prior to intracellular production of cAMP to suppress their response to FSH. When other cultures were treated with pertussis toxin, a blocker of intracellular GTP-binding proteins such as Gi, before sequential addition of endorphin and FSH, the effect of beta-endorphin on FSH-responsiveness was abolished. Moreover, when other cultures were exposed to pertussis toxin in the absence of endorphin, followed by FSH, their response to the hormone was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

The hybrids of carp, Cyprinus carpio L., and goldfish, Carassius auratus (L.), collected from the lower Great Lakes between 1978 and 1981 exhibited epizootics of gonadal neoplasms which were rare in the parental species. The gonadal histology of male and female carp captured for this study was typical of a successfully reproducing population but the hybrids appeared to be sterile. In male hybrids meiosis was often completed, but spermatids usually degenerated in early spermiogenesis. In female hybrids, vitellogenesis was frequently completed but there was no evidence of final maturation or ovulation. Proliferations of undifferentiated germ cells and stromal cells were evident in the tumour nodules of both the male and female hybrids and were considered to represent neoplastic transformations. Proliferations of Sertoli cells were common in males and in the male portion of intersex gonads, which were present in some hybrids. The Sertoli cells of these individuals were well differentiated, formed tubules and accumulated large stores of lipid. Extensive degeneration of germinal cells was often apparent in areas of Sertoli cell proliferation as were numerous, large, melano-macrophage centres. Gonadal stromal cell tumours did not form tubules or accumulate lipid. The spindle cells of these neoplasms could be found in homogeneous sheets or intermixed to varying degrees with the early stages of germ cells and/or connective tissue elements.