Abnormalities in functional development of the Sertoli cells in rats treated neonatally with diethylstilbestrol: a possible role for estrogens in Sertoli cell development

Effects of low-dose bisphenol AF on mammal testis development via complex mechanisms: alterations are detectable in both infancy and adulthood

Despite growing concern about adverse effects of bisphenol AF (BPAF) due to its endocrine disrupting properties, there is a lack of toxicity data from low-dose studies and direct evidence linking its adverse effects to endocrine disrupting properties. Here, we investigated the effects of gestational and postnatal exposure to BPAF through drinking water (0.15-15 μg/mL, equivalent to the daily intake of ~ 50 and 5 mg/kg/day) on testis development in mice. We found that like mestranol, 5 mg/kg/day BPAF resulted in remarkable decreases in multiple male reproductive parameters in adulthood, such as the sperm number and serum testosterone level. Notably, 50 μg/kg/day BPAF also caused significant decreases in anogenital distance (AGD), the luteinizing hormone level and spermatocyte number, along with declining trends in sperm number and the serum levels of testosterone and follicle-stimulating hormone. In line with the adverse outcomes observed in adulthood, on postnatal day (PND) 9, we also observed BPAF-caused dose-dependent alterations, including reduced AGD, seminiferous tubule area and numbers of total germ cells, spermatocytes and Leydig cells, coupled with down-regulated expression of male-biased genes in testes. Even when exposure to 5 mg/kg/day BPAF as well as MES was initiated from PND 0, similar alterations in male reproductive parameters were also found on PND 9, along with a decrease in the GnRH content in the hypothalamus; moreover, testicular alterations and the reduction in AGD were partly antagonized by the estrogen receptor (ER) antagonist ICI 182,780, but the reduction of GnRH production was not done, showing that the effects of BPAF on testis development may be partially mediated by ER signaling. In conclusion, all the findings demonstrate that low-dose BPAF can partly disrupt mammal testis development and cause adverse testicular outcomes in adulthood, indicating a potential reproductive risk to mammals including humans. Importantly, our finding that developmental alterations elicited by BPAF have been detectable on PND 9 provides important motivation for the development of effective methods for early detection of adverse effects of estrogenic chemicals on testis development.

Estradiol modulated differentiation and dynamic growth of CD90+ spermatogonial stem cells toward Sertoli-like cells

Mouse CD90⁺ SSCs were enriched using the MACS technique and incubated with different doses of estradiol, ranging from 0.01 ng/mL to 500 μg/mL, for 7 days. The viability of SSCs was determined using an MTT assay. The combined effects of estradiol plus Sertoli cell differentiation medium on the orientation of SSCs toward Sertoli-like cells were also assessed. Using immunofluorescence imaging, we monitored protein levels of Oct3/4 after being exposed to estradiol. In addition, protein levels of testosterone, TF, and ABP were measured using ELISA. The expression of Sertoli cell-specific genes such as SOX9, GATA4, FSHR, TF, and ESR-1 and -2 was monitored using real-time PCR assay, and the effects of 14-day injection of estradiol on sperm parameters and Oct3/4 positive progenitor cells in a model of mouse were determined. Data showed that estradiol increased the viability of mouse SSCs in a dose-dependent manner compared to the control (p < 0.05). Along with these changes, cells displayed morphological changes and reduced Oct3/4 transcription factor levels compared to the control SSCs. 7-day incubation of SSCs with estradiol led to the up-regulation of SOX9, GATA4, FSHR, TF, and ESR-1 and -2, and levels of testosterone, TF, and ABP were increased compared to the control group (p < 0.05). The in-vivo examination noted that estradiol reduced sperm parameters coincided with morphological abnormalities (p < 0.05). Histological examination revealed pathological changes in seminiferous tubules and reduction of testicular Oct3/4⁺ progenitor cells. In conclusion, estradiol treatment probably can induce Sertoli cell differentiation of SSCs while exogenous administration leads to testicular progenitor cell depletion and infertility in long term.

Estrogens and development of the rete testis, efferent ductules, epididymis and vas deferens

Estrogen has always been considered the female hormone and testosterone the male hormone. However, estrogen's presence in the testis and deleterious effects of estrogen treatment during development have been known for nearly 90 years, long before estrogen receptors (ESRs) were discovered. Eventually it was learned that testes actually synthesize high levels of estradiol (E2) and sequester high concentrations in the reproductive tract lumen, which seems contradictory to the overwhelming number of studies showing reproductive pathology following exogenous estrogen exposures. For too long, the developmental pathology of estrogen has dominated our thinking, even resulting in the "estrogen hypothesis" as related to the testicular dysgenesis syndrome. However, these early studies and the development of an Esr1 knockout mouse led to a deluge of research into estrogen's potential role in and disruption of development and function of the male reproductive system. What is new is that estrogen action in the male cannot be divorced from that of androgen. This paper presents what is known about components of the estrogen pathway, including its synthesis and target receptors, and the need to achieve a balance between androgen- and estrogen-action in male reproductive tract differentiation and adult functions. The review focuses on what is known regarding development of the male reproductive tract, from the rete testis to the vas deferens, and examines the expression of estrogen receptors and presence of aromatase in the male reproductive system, traces the evidence provided by estrogen-associated knockout and transgenic animal models and discusses the effects of fetal and postnatal exposures to estrogens. Hopefully, there will be enough here to stimulate discussions and new investigations of the androgen:estrogen balance that seems to be essential for development of the male reproductive tract.

Relevance of the Isoflavone Absorption and Testicular Function: A Systematic Review of Preclinical Evidence

Isoflavone is a phytoestrogen found in different types of food that can act as endocrine disrupters leading to testicular dysfunction. Currently, fragmented data on the action of this compound in the testicles make it difficult to assess its effects to define a safe dose. Thus, we systematically reviewed the preclinical evidence of the impact of isoflavone on testicular function. We also determined which form (aglycones or glycosylated) was the most used, which allowed us to understand the main biological processes involved in testicular function after isoflavone exposure. This systematic review was carried out according to the PRISMA guidelines using a structured search on the biomedical databases MEDLINE (PubMed), Scopus, and Web of Science, recovering and analyzing 22 original studies. The bias analysis and the quality of the studies were assessed by the criteria described in the risk of bias tool developed by SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation). The aglycones and glycosylated isoflavones proved to be harmful to the reproductive health, and the glycosylates at doses of 50, 100, 146, 200, 300, 500, and 600 mg/kg, in addition to 190 and 1000 mg/L, appear to be even more harmful. The main testicular pathologies resulting from the use of isoflavones are associated with Leydig cells resulting from changes in molecular functions and cellular components. The most used isoflavone to evaluate testicular changes was the genistein/daidzein conjugate. The consumption of high doses of isoflavones promotes changes in the functioning of Leydig cells, inducing testicular changes and leading to infertility in murine models.

Cypermethrin exposure during perinatal period affects fetal development and impairs reproductive functions of F1 female rats

Cypermethrin (CYP) is a ubiquitously present synthetic pyrethroid insecticide. It has endocrine disrupting activities which may adversely affect reproductive development and functions of offspring if exposed during critical developmental period. The present study was undertaken to delineate the effects of CYP exposure in pregnant female rats during perinatal period on the sexual maturation, hormonal regulation, reproductive development and fertility of F1 female offspring and its molecular mechanism of action. Pregnant rats (F0) were gavaged daily with 0, 1, 10, 25 mg/kg bw/day CYP and 10 μg/kg bw/day Diethylstilbestrol (DES; positive control) from gestation day (GD) 6 to postnatal day (PND) 21. The reproductive development and function parameters were evaluated at PND 45 and 75. Reduced body weight, delayed vaginal opening, and disrupted estrous cyclicity were observed at 25 mg/kg CYP dose. CYP exposure significantly affected the reproductive organ development and their functions at all doses. Significant alterations in ovarian and uterine histology such as luteinization, reduction of primordial follicular reserves, presence of multi-oocyte follicles and thin degenerative luminal and glandular uterine epithelium were observed at adulthood. Altered circulatory steroid hormone levels and expression of ovarian and uterine steroid hormone receptors were observed at PND 75 in the F1 female offspring. Expression of HOXA10 and α-SMA which are important for uterine integrity and functions, were found to be altered at PND 75. Increased pre-implantation loss (PIL%), post-implantation loss (POL%), and reduced litter size in F1 females when cohabitated with unexposed fertile male rats were observed. Overall, perinatal exposure of pregnant rats to CYP led to significant long lasting effects on the reproductive functions of F1 female offspring. The adverse effects were passed on to F2 generation via female germ line and posed developmental anomalies. The present finding necessitates additional molecular studies to understand its trans-generational mechanism of action via female germline.

Embryonic cadmium exposure of male rats alters reproductive functions at adulthood, but without overt alterations in developmental and behavioral outcomes and metabolism

The effects of exposure of pregnant rats to cadmium (Cd) on the developmental and behavioral outcomes, reproductive functions, and metabolism of their male progeny were evaluated. Rats (Wistar) were injected intraperitoneally with either 0.5 or 5.0 µg Cd/kg body weight from day 12 to day 19 of pregnancy. The male offspring were evaluated for their developmental outcomes and behavioral changes. All developmental and behavioral parameters assessed were comparable among the different groups. All male pups were allowed to develop until 100 days of age and evaluated for reproductive end points. The results revealed that although the body weights and relative weights of liver, brain, kidney, testis, and epididymis were not altered, reproductive parameters, including daily sperm production, epididymal sperm numbers, and concentrations of motile, viable, and hypo-osmotic tail-swelled sperm declined significantly in rats exposed to 0.5 and 5.0 µg Cd during embryonic development. In addition, plasma testosterone levels and activity levels of testicular steroidogenic enzymes also decreased in these rats. In the fertility study, although each male in the 0.5, 5.0 µg, and control groups produced a copulatory plug and impregnated a female, the mean number of implantations and live fetuses was reduced significantly in females mated with rats exposed to 0.5 and 5.0 µg Cd during the prenatal period. The general metabolism of the animals exposed to Cd during embryonic development was comparable with the controls as evidenced by no significant changes in the activity levels of succinate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, aspartate aminotransaminase, and alanine aminotransaminases in the liver, kidney, and testis. The results thus suggest that maternal Cd exposure during embryonic development markedly affected the spermatogenesis, steroidogenesis, and fertility potential, but without alterations in the development, behavior, and metabolism.

Recovery of Prenatal Baicalein Exposure Perturbed Reproduction by Postnatal Exposure of Testosterone in Male Mice

Baicalein (BC), a flavonoid, which lacks the qualities of reproductive health and shows adverse effects, is tested in this study. Inseminated mice were injected with 30, 60, and 90 mg BC/Kg body weight on gestation days 11, 13, 15, and 17. The F1 BC-exposed males of each dosage were divided into six groups. First three groups (n = 6 from each BC dosage) were used for assessment of reproductive performance, the others (n = 4 from each BC dosage) were administered with testosterone 4.16 mg/kg body weight on postnatal days 21, 31, and 41. The reproductive health of adult F1 males at the age of 55 and 60 was tested. Prenatal BC exposure showed reduced fertility after cohabitation with control females. The BC exposure significantly reduced the body weight, tissue indices, and sperm parameters (motility, count, viability, and daily sperm count) and altered the sperm membrane in a hypoosmotic swelling test. A downward trend was observed in testicular steroidogenic marker enzymes (3β- and 17β-steroid dehydrogenases) and serum testosterone, whereas increase in serum titers of FSH and LH along with altered the testicular histology. Conversely, testosterone (4.16 mg/kg body weight) partially recovered reduced male reproductive health by BC. BC impaired male reproductive health due to low levels of testosterone is reverted by external testosterone is evidenced in this study.

Gestational Exposure to Synthetic Steroid Hormones Impaired Sperm Quantity and Quality in Wistar Rats

This study was designed to investigate the effect of prenatal exposure to synthetic sex steroid on sperm quantity and quality, relative testicular and epididymal weights, and reproductive hormones level in adult Wistar rats. Forty male Wistar rats were divided into two groups: a test group (n = 20) that included mature rats that were born to dams exposed to gestational treatment with hydroxyprogesterone and a control group (n = 20) that included mature rats born to untreated dams. Compared to the control group, the test group showed a significant reduction in the sperm count, viability and motility, relative testicular and epididymal weights together with increased abnormal spermatozoa (p < 0.001). The reproductive hormonal assay revealed significantly lower serum testosterone and higher levels of FSH and LH among the test groups compared to the control (p < 0.05 for all). Prenatal exposure to synthetic progesterone negatively affected sperm production and function, relative testicular and epididymal weights, and reproductive hormone levels.

Diethylstilbestrol induces morphological changes in the spermatogonia, Sertoli cells and Leydig cells of adult rat

It is now established that diethylstilbestrol (DES) has damaging effects on the male reproductive system. However, to date there have been no studies morphological analysis of adult rat testes upon treatment with DES. Here, we examined whether DES has any significant morphological effect on steroidogenesis and spermatogenesis. DES was injected subcutaneously at 3 μg/day and 30 μg/day in adult male Sprague-Dawley (SD) rats for two different treatment lengths (1 or 3 weeks), after which rats were necropsied. TUNEL labeling, cell counting, and morphological analysis were used to evaluate the effects of DES. A high dose of DES and longer exposure severely affected the cellular development of the testis. Specifically, DES treatment disrupted both steroidogenesis and spermatogenesis by decreasing the number of spermatogonia, Sertoli cells, and Leydig cells in a dose- and time-dependent manner. Thus, DES may account for decreases in the number of spermatogenic cells, Sertoli cells and Leydig cells, which in turn may lead to reduced fertility in males.

Testicular histomorphometrics including Sertoli cell quantitation for evaluating hatchability and fertility issues in commercial breeder-broiler roosters

Testicular histomorphometric methods were developed for the investigation of fertility and hatchability problems in commercial broiler-breeder roosters. Sertoli cell (SC) evaluations were emphasized in view of their role in influencing embryonic testicular organogenesis and spermatogenesis in adults. H&E stained sections prepared from formalized tissues were examined. SC evaluations were mostly made from computer generated images using image analysis software, but were also compared to direct counting with ocular grid reticle. Other measurements were germinal epithelial and total seminiferous tubule widths, quantification of individual spermatozoa and sperm clusters, and determinations of stromal area. Age-associated changes in SC occurred between 15 to 54 wk of age. A significant reduction in SC concentration occurred at 29 wk of age (P < 0.001) that corresponded with the histologic initiation of spermatogenesis. Expanded morphometric evaluations were performed on 59-week-old roosters comparing a flock having good body condition and footpad scores with normal testicular and body weights (optimal profile or OP group) to a second flock demonstrating relatively poor expression of these parameters and decreased fertility (sub-optimal profile or SOP group). Significant reductions (P < 0.05) in SC concentration, spermatozoa, and tubular widths, but an increased percentage of stroma area occurred in SOP compared to OP flocks. SC results also correlated well with testes weight. A unique finding was a significant relationship between decreasing SC concentration and increasing severity scores for footpad lesions. Differences in all histomorphometric parameters occurred between flocks demonstrating good hatchability compared to flocks exhibiting either low or decreasing hatchability. Significant reductions in SC and other morphometric parameters were observed for the poor relative to good hatchability group. A strong positive association was observed for SC results using computer generated images and direct reticle ocular counting (R = 0.80). Replicate counts on control sections demonstrated generally good reproducibility of methods between experiments. The findings are supportive of the value of testicular histomorphometrics for evaluations of hatchability issues in commercial roosters.

Perinatal exposure of pregnant rats to cypermethrin delays testicular descent, impairs fertility in F1 male progeny leading to developmental defects in F2 generation

Cypermethrin (CYP) is a widely used synthetic pyrethroid insecticide and regarded as a potential endocrine disruptor. CYP exposure may pose a great risk to human health including adverse effect on their reproductive functions. This study aimed to delineate the effects of perinatal exposure of rats to CYP on the sexual maturation and fertility of F1 male progeny. Pregnant rats (F0) were gavaged daily with CYP (0, 1, 10, 25 mg/kg BW/day) and Diethylestilbestrol (DES, 10 μg/kg BW/day), as positive control from gestation day 6 to postnatal day 21. The effects of CYP on body weight gain and reproductive functions were evaluated at the Juvenile (PND 22), peri-pubertal (PND 45) and adult (PND 75) stages of development. A significant delay in the age of testicular descent and prepuce separation was observed at 1 and 25 mg/kg doses of CYP. At the same dose level, reproductive organ development and their functions were also affected. A significant alteration in testicular histology, expression of steroid hormone receptors, and circulatory steroid hormones was observed throughout development. Reduced sperm count and motility were observed at PND 75 leading to subfertility and reduced litter size. These adult male rats when cohabitated with unexposed normal cycling females, the F2 fetuses exhibited developmental defects. Taken together, CYP perinatal exposure caused significant long lasting effects of the reproductive functions of F1 generation male rats, which were vertically transmitted to F2 generation leading to developmental defects. The mechanism of transgenerational effects needs to be explored in details.

Prenatal and postnatal exposure to low levels of permethrin exerts reproductive effects in male mice

Permethrin, a pyrethroid chemical, is widely used as a pesticide because of its rapid insecticidal activity. Although permethrin is considered to exert very low toxicity on mammalian reproductive organs, the effects of early low-level and chronic exposure on adult spermatogenesis are unclear. We exposed mice to environmentally relevant concentrations of permethrin (0, 0.3, and 30ppm) in drinking water during prenatal and postnatal period and examined the effects on the testis in mice offspring when they reached maturity (12 weeks of age). Using methyl green-pyronin staining, we found an abnormal accumulation of RNA in the seminiferous epithelia of mice treated with permethrin; this accumulation may be derived from an enlargement of the residual body. Additionally, permethrin may cause a decline of Sertoli cell functions. Our findings demonstrate that low-level and chronic permethrin exposure during prenatal and postnatal period has distinct effects on male reproductive system in mice.

Low Birth Weight Is Associated with a Decreased Overall Adult Health Status and Reproductive Capability - Results of a Cross-Sectional Study in Primary Infertile Patients

Individuals born with low birth weight (LBW) risk cardiometabolic complications later in life. However the impact of LBW on general health status and male reproductive function has been scantly analysed. We investigated the clinical and seminal impact of different birth weights (BW) in white-European men presenting for primary couple's infertility. Demographic, clinical, and laboratory data from 827 primary infertile men were compared with those of 373 consecutive fertile men. Patients with BW ≤2500, 2500-4200, and ≥4200gr were classified as having LBW, normal (NBW), and high BW (HBW), respectively. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Testicular volume was assessed with a Prader orchidometer. Semen analysis values were assessed based on 2010 WHO reference criteria. Descriptive statistics and regression models tested associations between semen parameters, clinical characteristics and BW categories. LBW, NBW and HBW were found in 71 (8.6%), 651 (78.7%) and 105 (12.7%) infertile men, respectively. LBW was more frequent in infertile patients than fertile men (p = 0.002). Infertile patients with LBW had a higher rate of comorbidities (p = 0.003), lower mean testicular volume (p = 0.007), higher FSH (p = 0.02) and lower tT levels (p = 0.04) compared to other BW groups. Higher rates of asthenozoospermia (p = 0.02) and teratozoospermia (p = 0.03) were also found in LBW men. At logistic regression models, LBW was univariably associated with pathologic progressive motility (p≤0.02) and pathologic sperm morphology (p<0.005). At multivariable logistic regression analysis, LBW achieved independent predictor status for both lower sperm motility and pathologic sperm morphology (all p≤0.04). Only LBW independently predicted higher CCI values (p<0.001). In conclusion, we found that LBW was more frequent in infertile than in fertile men. Infertile individuals with LBW showed a higher rate of comorbidities and significantly worse clinical, endocrine and semen parameters compared to other BW groups.

Altered spermatogenesis, steroidogenesis and suppressed fertility in adult male rats exposed to genistein, a non-steroidal phytoestrogen during embryonic development

This article focuses on the effects of prenatal exposure to genistein on the mother, her pregnancy and reproductive functions of the male progeny, since these issues have ethological relevance in both animals and humans. Pregnant Wistar rats received i.p. injections of genistein at a dose level of 2, 20 or 100 mg/kg body weight daily from 12^th to 19^th day of gestation. Male pups from control and genistein exposed animals were weaned and allowed to develop until 100 days of age; however, when they were 90 days old, twelve males from each group were cohabited with untreated 90-day old females for 8 days. Results revealed a significant decrease in indices of reproductive organs in adult male rats exposed to genistein during embryonic development. Dose dependent reduction was observed in daily sperm production and epididymal sperm density and quality in genistein treated rats. Significant decrease was observed in the activity levels of 3β- and 17β-hydroxysteroid dehydrogenases in testis of experimental rats with a decline in plasma testosterone levels. Histological examination of testis of genistein treated rats indicated deterioration in testicular architecture. In the fertility study, the mean number of implantations and live fetuses per dam mated with 100 mg genistein exposed males was reduced.

Mammary Gland Evaluation in Juvenile Toxicity Studies: Temporal Developmental Patterns in the Male and Female Harlan Sprague-Dawley Rat

There are currently no reports describing mammary gland development in the Harlan Sprague-Dawley (HSD) rat, the current strain of choice for National Toxicology Program (NTP) testing. Our goals were to empower the NTP, contract labs, and other researchers in understanding and interpreting chemical effects in this rat strain. To delineate similarities/differences between the female and male mammary gland, data were compiled starting on embryonic day 15.5 through postnatal day 70. Mammary gland whole mounts, histology sections, and immunohistochemically stained tissues for estrogen, progesterone, and androgen receptors were evaluated in both sexes; qualitative and quantitative differences are highlighted using a comprehensive visual timeline. Research on endocrine disrupting chemicals in animal models has highlighted chemically induced mammary gland anomalies that may potentially impact human health. In order to investigate these effects within the HSD strain, 2,3,7,8-tetrachlorodibenzo-p-dioxin, diethylstilbestrol, or vehicle control was gavage dosed on gestation day 15 and 18 to demonstrate delayed, accelerated, and control mammary gland growth in offspring, respectively. We provide illustrations of normal and chemically altered mammary gland development in HSD male and female rats to help inform researchers unfamiliar with the tissue and may facilitate enhanced evaluation of both male and female mammary glands in juvenile toxicity studies.

Epigenetic effects of prenatal estradiol-17β exposure on the reproductive system of pigs

There is growing evidence that early life exposure to endocrine disrupting chemicals might increase the risk for certain adult onset diseases, in particular reproductive health problems and hormone dependent cancers. Studies in rodents suggest that perinatal exposure to even low doses of estrogenic substances can cause adverse effects, including epigenetic reprogramming of the prostate and increased formation of precancerous lesions. We analyzed the effects of an in utero exposure to the strongest natural estrogen, estradiol-17β, in a pig model. Two different low and one high dose of estradiol-17β (0.05, 10 and 1000 μg/kg body weight/day) were orally applied to gilts during pregnancy and potential effects on the reproductive system of the offspring were analyzed. No significant effects on sperm vitality parameters and testes size were observed in adult boars. However, prenatal exposure to the high dose decreased absolute, but not relative weight of the testes in prepubertal piglets. RNA sequencing revealed significantly regulated genes of the prepubertal prostate, while testes and uteri were not affected. Notably, we found an increased prostate expression of CCDC80 and a decreased ADH1C expression in the low dose treatment groups. BGN and SPARC, two genes associated with prostate tumor progression, were as well more abundant in exposed animals. Strikingly, the gene body DNA methylation level of BGN was accordingly increased in the high dose group. Thus, while only prenatal exposure to a high dose of estrogen altered testes development and local DNA methylation of the prostate, even low dose exposure had significant effects on gene expression in the prostate of prepubertal piglet offspring. The relevance of these distinct, but subtle transcriptional changes following low dose treatment lacking a clear phenotype calls for further long-term investigations. An epigenetic reprogramming of the pig prostate due to prenatal estrogen cannot be neglected.

Phthalate affect the reproductive function and sexual behavior of male Wistar rats

Phthalates are chemicals used in many industrial products (plastic toys, shampoos, soaps), and are suspected of inducing adverse effects on the male reproductive system. In the present study, we evaluated the effects of the plasticizer di-(2-ethylhexyl)-phthalate (DEHP) on the reproductive function and sexual behavior of male offspring rats, exposed in utero and during lactation (0, 20, 100 and 500 mg/kg per day by gavage). The effects produced clearly demonstrate the ability of DEHP to disrupt the androgen-regulated development of the male reproductive tract. Absolute and relative weights of androgen-dependent tissue organs (ventral prostate and seminal vesicle) were significantly reduced at the highest dose level tested (500 mg/kg per day). Impairment of male sexual behavior (500 mg/kg per day) was also observed. Moreover, the reduction in daily sperm production and epididymal sperm counts observed after administration of the highest dose suggests an impairment of the spermatogenic processes. Most of the adverse effects reported here were observed both during puberty and during adulthood, indicating permanent effects of in utero and lactational DEHP exposure.

Xenoestrogens diethylstilbestrol and zearalenone negatively influence pubertal rat's testis

The aim of this study was to assess the impact of xenoestrogens: diethylstilbestrol (DES) and zearalenone (ZEA) on rat's pubertal testis and to compare it with the effect of natural estrogen - 17beta-estradiol (E). Male Wistar rats were daily, subcutaneously injected at 5th-15th postnatal days (p.d.) with E (1.25 or 12.5 mug) or DES (1.25 or 12.5 mug) or ZEA (4 or 40 mug) or vehicle. At 16th p.d. testes were dissected, weighted, and paraffin embedded. Following parameters were assessed: diameter and length of seminiferous tubule, numbers of spermatogonia A+intermediate+B (A/In/B), preleptotene spermatocytes (PL), leptotene+zygotene+pachytene spermatocytes (L/Z/PA) and Sertoli cells per testis. Testes weight, seminiferous tubule diameter and length were decreased by both doses of E, DES and ZEA. DES effect was the strongest, but its influence on testis weight and seminiferous tubule length, on the contrary to E and ZEA, was not dose-dependent. Similarly, DES in both doses had the most severe negative impact on the number of germ and Sertoli cells. The negative influence of E on germ cells was less pronounced. The negative effect of ZEA was seen only after administration of the higher dose on spermatogonia number, while DES and E decreased A/In/B number more evidently. Sertoli cell number were decreased after both doses of E. ZEA40 decreased Sertoli cell number while ZEA4 had no effect.

CONCLUSION

exposure of prepubertal male rat to DES has the strongest detrimental effect on the developing testis in comparison to E and ZEA. Both, E and DES, decreased number of germ and Sertoli cells, diminished seminiferous tubule diameter, length and testis weight. ZEA had much more weaker effect than the potent estrogens.

Comparison of the effects of bisphenol A alone and in a combination with X-irradiation on sperm count and quality in male adult and pubescent mice

Bisphenol A (BPA) is employed in the manufacturing of epoxy, polyester-styrene, and polycarbonate resins, which are used for the production of baby and water bottles and reusable containers, food and beverage packing, dental fillings and sealants. The study was designed to examine the effects of 8-week exposure (a full cycle of spermatogenesis) to BPA alone and in a combination with X-irradiation on the reproductive organs and germ cells of adult and pubescent male mice. Pzh:Sfis male mice were exposed to BPA (5, 10, and 20 mg/kg) or X-rays (0.05 Gy) or to a combination of both (0.05 Gy + 5 mg/kg bw BPA). The following parameters were examined: sperm count, sperm motility, sperm morphology, and DNA damage in male gametes. Both BPA and X-rays alone diminished sperm quality. BPA exposure significantly reduced sperm count in pubescent males compared to adult mice, with degenerative changes detected in seminiferous epithelium. This may suggest a higher susceptibility of germ cells of younger males to BPA action. Combined BPA with X-ray treatment enhanced the harmful effect induced by BPA alone in male germ cells of adult males, whereas low-dose irradiation showed sometimes protective or additive effects in pubescent mice.

Sexually dimorphic transcription of estrogen receptors in cod gonads throughout a reproductive cycle

The role of sex steroid regulation in gonadal maturation is a very complex process that is far from being fully understood. Hence, we have investigated seasonal changes in gonadal expression of estrogen receptors (ERs) in Atlantic cod (Gadus morhua L.), a batch spawner, throughout the annual reproductive cycle. Three nuclear ER partial cDNA sequences (esr1, esr2a, and esr2b) were cloned and all esr transcripts were detected mainly in liver and gonads of fish of both sexes. In situ hybridization of esrs along with germ cell (vasa) and gonadal somatic cell markers (gonadal soma-derived factor (gsdf), 3β-hydroxysteroid dehydrogenase (3βhsd), and anti-Müllerian hormone (amh) for testicular, or gsdf for ovarian somatic cells) showed that all three esrs were preferentially localized within interstitial fibroblasts composed of immature and mature Leydig cells in testis, whereas they were differentially expressed in both follicular cells and oocytes in ovary. Quantitative real-time PCR analysis revealed a sexually dimorphic expression pattern of the three esr paralogs in testis and ovary. A significant increase in esr2a expression was identified in testis and of esr2b in ovary, whereas esr1 transcripts were elevated in both testis and ovary in February and March before the spawning period. The localization and sexually dimorphic expression of esr genes in gonads indicate a direct function of estrogen via ERs in gonadal somatic cell growth and differentiation for Leydig cell in testis and follicular cells in ovary throughout the annual reproductive cycle in Atlantic cod.

Differential expression of aromatase, estrogen receptor alpha and 17β-HSD associated with the processes of total testicular regression and recrudescence in the bat Myotis nigricans (Chiroptera: Vespertilionidae)

Despite the worldwide distribution and many unique reproductive adaptations that bats present, many aspects of their reproductive hormonal regulation have not been adequately studied, especially in species that presented patterns of total testicular regression. Thus, this study aimed to evaluate the testicular expression of 17β-HSD type 1, aromatase and ERα in the bat Myotis nigricans, during the four periods of its reproductive cycle. Immunoreactivity for ERα was detected only in the cytoplasm of elongated spermatids and in the nuclei of spermatogonia and Sertoli cells. Expression of aromatase was observed in round and elongated spermatids and in Sertoli and Leydig cells. Immunoreactivity for 17β-HSD was restricted to the cytoplasm of Leydig cells. The three expression patterns varied significantly during the four periods of the reproductive cycle. Expression of ERα and aromatase in spermatids was continuous, while expression of ERα in spermatogonia occurred only in initial types (Ap). Expression of ERα and aromatase in Sertoli cells varied, with expression only in periods of spermatogenetic activities; and the same variation was observed for the expression of aromatase and 17β-HSD in Leydig cells. We, therefore, propose that the processes of total testicular regression and posterior recrudescence suffered by M. nigricans from September to January in the northwest of the São Paulo State of Brazil, are directly regulated by testosterone and estrogen. This occurs via the production of testosterone by 17β-HSD, its conversion into estrogen by aromatase, and activation/deactivation of Sertoli cells' AR and spermatogonia's ERα.

Effects of n-butylparaben on steroidogenesis and spermatogenesis through changed E₂ levels in male rat offspring

Parabens are widely used as antibacterial agents, which are concerned recently in the relationship between the use of parabens and reproductive toxicity. So that reassessment of the risk of parabens is needed. In this study, one of parabens, n-butylparaben (n-BP) was orally administered to pregnant Wistar rats (0, 64, 160, 400 and 1000 mg/kg/day) from gestation day (GD) 7 through postnatal day (PND) 21. Reduced anogenital distance (AGD) and delayed preputial separation (PPS) were observed in the male offspring. The weights of the testes were significantly reduced at PND 21-90. The weights of the epididymides were significantly reduced at all monitoring points, except PND 35. Seminal vesicle weights were significantly reduced on PND 21. Serum testosterone (T) was significantly decreased, especially on PND 49. The levels of 17β-estradiol (E2) showed an increase at each of the tested points except on PND 180. Serum luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels in the n-BP treated groups were lower on PND 21, 35 and 49 but elevated on PND 90 compared to control levels. n-BP reduced epididymal cauda sperm counts and daily sperm production in a dose-dependent manner; this difference was statistically significant at exposure groups of 400 and 1000 mg/kg/day. The present study strongly suggests that exposure to n-BP in utero and during lactation has adverse effects on the reproductive system in male offspring, with a no observed adverse effect level (NOAEL) of 160 mg/kg/day. To our knowledge, this is the first study that reports increased E2 levels of male rats following n-BP exposure; we suggest that E2 levels may be considered as biomarkers for some endocrine disrupting chemicals (EDCs).

Aberrant DNA methylation at Igf2-H19 imprinting control region in spermatozoa upon neonatal exposure to bisphenol A and its association with post implantation loss

Bisphenol A (BPA) is an estrogenic compound commonly used in manufacture of various consumer products. Earlier studies from our group have demonstrated that neonatal exposure of male rats to BPA causes decrease in sperm count and motility, increase in post implantation loss, ultimately leading to subfertility during adulthood. One of the factors contributing for post implantation loss is altered methylation pattern of imprinted genes. The present study was undertaken to investigate the molecular effects of neonatal exposure of male rats to BPA (2.4 μg/pup) (F0) on the methylation of H19 imprinting control region (ICR) in resorbed embryo (F1) and compared with spermatozoa of their respective sires (F0). We observed a significant down regulation in the transcript expression of Igf2 and H19 genes in BPA resorbed embryo (F1) as compared to control viable embryo. A significant hypomethylation was observed at the H19 ICR in the spermatozoa as well as in resorbed embryo sired by rats exposed neonatally to BPA. These results indicated that the aberrant methylation at ICR in spermatozoa was inherited by embryo which causes perturbation in the expression of Igf2 and H19, ultimately leading to post implantation loss. This could be one of the possible mechanisms of BPA induced adverse epigenetic effects on male fertility.

The blood-testis barrier and its implications for male contraception

The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.

Effects of in utero exposure to Bisphenol A or diethylstilbestrol on the adult male reproductive system

The objective of this study was to determine whether in utero exposure to Bisphenol A (BPA) induced reproductive tract abnormalities in the adult male testis. Using the C57/Bl6 mouse, we examined sex-organ weights, anogenital distance, and testis histopathology in adult males exposed in utero via oral gavage to sesame oil, 50 µg/kg BPA, 1000 µg/kg BPA, or 2 µg/kg diethylstilbestrol (DES) as a positive control from gestational days 10 to 16. No changes in sperm production or germ cell apoptosis were observed in adult testes after exposure to either chemical. Adult mRNA levels of genes associated with sexual maturation and differentiation, GATA4 and ID2, were significantly lower only in DES-exposed testes. In summary, the data indicate no gross alterations in spermatogenesis after in utero exposure to BPA or DES. At the molecular level, in utero exposure to DES, but not BPA, leads to decreased mRNA expression of genes associated with Sertoli cell differentiation.

Exposure to diethylstilbestrol during embryonic and larval stages of medaka fish (Oryzias latipes) leads to sex reversal in genetic males and reduced gonad weight in genetic females

Molecular and cellular mechanisms involved in artificially induced ovarian differentiation were analyzed by exposing embryos of medaka (Oryzias latipes) to a potent nonsteroidal estrogen, diethylstilbestrol (DES). Embryos were exposed for short-exposure (SE) [from 0 to 8 d postfertilization (dpf)] and long-exposure (LE) periods (from 0 to 18/28 dpf) to 1 ng/ml of DES, and status of sexual differentiation in somatic and germ cells of these gonads was analyzed at 8, 18, and 28 dpf by histology, cell proliferation assays, TUNEL assay, and in situ hybridization using sex-specific somatic and germ cell markers. Additionally, gonads of exposed fry were examined after withdrawal of DES to see whether effects of DES in exposed fish were reversible or not. DES induced germ cell proliferation and meiosis in XY fry of SE and LE groups. However, SE induced only a partial reduction in expression of gonadal soma-derived factor, the male-dominant somatic cell marker, and was not sufficient to induce ovarian development after withdrawal of DES. On the contrary, LE resulted in complete loss of such male-specific gene expression in somatic cells of XY gonads, and these gonads underwent sustained ovarian development even after withdrawal of DES. Importantly, LE to DES affected germ cell proliferation in XX gonads adversely during early stages of sexual differentiation, leading to reduced gonad weight in adulthood. Interestingly, apoptosis was not the cause for reduction in germ cell number. Taken together, these results indicated that DES exposure has long-lasting effects on the gonadal development in genetic males (sex reversal) and females (reduced gonad weight) of medaka.

Embryonic exposure to octylphenol induces changes in testosterone levels and disrupts reproductive efficiency in rats at their adulthood

The purpose of the present study was to investigate the effects of prenatal exposure to octylphenol (OP) at the dose of 50mg/kg body weight on days 1, 7 and 14 of pregnancy on reproductive health of male rats at adulthood. F1 male rats from control and OP exposed animals were weaned and maintained up to postnatal day (PND) 100. The indices of testis, epididymis and seminal vesicles were significantly decreased in male rats exposed to OP during embryonic development when compared with controls. Significant reduction in the epididymal sperm count, viable sperms and motile sperms and number of tail coiled sperms (HOS-test) were observed in experimental rats when compared to control rats. The levels of serum testosterone and also activity levels of testicular hydroxysteroid dehydrogenases were significantly decreased with a significant increase in the serum follicle stimulating and leutinizing hormones in experimental rats. Furthermore, embryonic exposure to OP caused significant down regulation of StAR, 3ß hydroxysteroid dehydrogenase and 17ß hydroxysteroid dehydrogenase mRNAs in testis of adult rats as compared to control rats. The results of fertility studies revealed that there was an increase in the mating index in experimental rats with an increase in the pre- and post-implantation losses in rats cohabited with treated animals indicating poor male reproductive performance.

GDNF stimulates the proliferation of cultured mouse immature Sertoli cells via its receptor subunit NCAM and ERK1/2 signaling pathway

Background

The proliferation and final density of Sertoli cells in the testis are regulated by hormones and local factors. Glial cell line-derived neurotrophic factor (GDNF), a distantly related member of the transforming growth factor-β superfamily, and its receptor subunits GDNF family receptor alpha 1 (GFRα1), RET tyrosine kinase, and neural cell adhesion molecule (NCAM) have been reported to be expressed in the testis and involved in the regulation of proliferation of immature Sertoli cells (ISCs). However, the expression patterns of these receptor subunits and the downstream signaling pathways have not been addressed in ISCs.

Results

In the present study, we have reported that the proliferation of cultured ISCs was significantly enhanced by GDNF. The receptor subunits GFRα1 and NCAM but not RET were expressed in ISCs, and the stimulatory effect of GDNF on the proliferation of ISCs was significantly reduced by anti-NCAM antibody blocking or siRNA that specifically targets NCAM mRNA. Additionally, the ERK1/2 inhibitor, PD98059, completely abolished the mitogenic effect of GDNF on ISCs.

Conclusions

GDNF stimulates the proliferation of ISCs via its receptor subunit NCAM and the consequent activation of the ERK1/2 signaling pathway.

Developmental programming: impact of excess prenatal testosterone on intrauterine fetal endocrine milieu and growth in sheep

Prenatal testosterone excess in sheep leads to reproductive and metabolic disruptions that mimic those seen in women with polycystic ovary syndrome. Comparison of prenatal testosterone-treated sheep with prenatal dihydrotestosterone-treated sheep suggests facilitation of defects by androgenic as well as androgen-independent effects of testosterone. We hypothesized that the disruptive impact of prenatal testosterone on adult pathology may partially depend on its conversion to estrogen and consequent changes in maternal and fetal endocrine environments. Pregnant Suffolk sheep were administered either cottonseed oil (control) or testosterone propionate in cottonseed oil (100 mg, i.m. twice weekly), from Day 30 to Day 90 of gestation (term is ~147 d). Maternal (uterine) and fetal (umbilical) arterial samples were collected at Days 64-66, 87-90, and 139-140 (range; referred to as D65, D90, and D140, respectively) of gestation. Concentrations of gonadal and metabolic hormones, as well as differentiation factors, were measured using liquid chromatography/mass spectrometer, radioimmunoassay, or ELISA. Findings indicate that testosterone treatment produced maternal and fetal testosterone levels comparable to adult males and D65 control male fetuses, respectively. Testosterone treatment increased fetal estradiol and estrone levels during the treatment period in both sexes, supportive of placental aromatization of testosterone. These steroidal changes were followed by a reduction in maternal estradiol levels at term, a reduction in activin A availability, and induction of intrauterine growth restriction in D140 female fetuses. Overall, our findings provide the first direct evidence in support of the potential for both androgenic as well as estrogenic contribution in the development of adult reproductive and metabolic pathology in prenatal testosterone-treated sheep.

Ontogeny of the oestrogen receptors ESR1 and ESR2 during gonadal development in the tammar wallaby, Macropus eugenii

Oestrogen has wide ranging effects in development mediated mainly via the two oestrogen receptors, α (ESR1, also known as ERα) and β (ESR2, also known as ERβ). Oestrogen is the key factor that directs the indifferent gonad to become an ovary in many non-mammalian vertebrates. Oestrogen is not required for early ovarian differentiation in mammals but can disrupt normal testicular development in eutherians. Surprisingly, exogenous oestrogen can cause sex reversal of an XY gonad in two marsupials, the North American opossum and the tammar wallaby. To understand the mechanism by which oestrogen induces sex reversal, we characterised the genes for ESR1 and ESR2 and examined their expression during gonadal differentiation in the tammar wallaby, Macropus eugenii. Both receptors were expressed in the somatic cells and germ cells of the indifferent gonad in both XX and XY foetuses throughout all stages of development, and persisted in these cells into adulthood. ERs were also present in many other tissues including kidney, pituitary and mammary gland. ER mRNA was not significantly altered by exogenous oestrogen in cultured XY gonads but the receptors translocated to the nucleus in its presence. These findings confirm that there is conserved expression of the ERs in the indifferent gonad despite the lack of available ligand during early gonadal development. The receptors can respond to exogenous estrogen at this early stage and are capable of transducing signals in the early mammalian gonad. However, the selective forces that maintained conserved ER expression in this tissue remain unknown.

Organotypic cultures of prepubertal mouse testes: a method to study androgen action in sertoli cells while preserving their natural environment

Cluster analysis at Postnatal Day 8-20 of putative androgen-regulated genes in mice with Sertoli cell-selective knockout of the androgen receptor (SCARKO) has pinpointed three genes (Spinlw1, Gpd1, Drd4) with an expression pattern strongly resembling that of Rhox5, the definitive Sertoli cell (SC) androgen-regulated gene. We used organotypic testis cultures from Day 8 mice to study control of these genes by (anti)androgens and follicle-stimulating hormone (FSH). Testis morphology and androgen induction of the studied genes were preserved for 48 h. Preincubation with ketoconazole for 24 h to block endogenous androgen production, followed by 24-h incubation with the synthetic androgen R1881, resulted in 45-, 5-, 19-, and 6-fold induction of mRNA levels of Rhox5, Spinlw1, Gpd1, and Drd4, respectively. However, noticeable differences in control of the studied genes were observed. Rhox5 and Spinlw1 were fully induced by R1881 in the continuous (48 h) presence of ketoconazole, whereas only marginal effects were observed on expression of Gpd1 and Drd4. Similarly, FSH only marginally affected expression of Rhox5 and Spinlw1, whereas it markedly increased Gpd1 and Drd4 expression. Explant cultures of SCARKO testes confirmed the differential effects of FSH on the studied genes and, for Gpd1, showed that the effect did not depend on a functional androgen receptor in SC, whereas this was essential for the effects of FSH on Drd4. In conclusion, organotypic cultures represent the first in vitro approach to preserving androgen responsiveness of putative SC-expressed genes. This approach facilitates detailed analysis of their regulation in ways not possible in vivo.

Neonatal estrogenic effects upon the male rat pituitary: early gonadotrophin attenuation precedes long-term recovery

Neonatal exposure to potent estrogenic compounds can affect multiple components of the male reproductive system causing impaired development of the epithelium and overgrowth of stromal tissue in the epididymis, vas deferens, seminal vesicles, and prostate. However, very little is known about the direct effects of estrogenic compounds on the anterior pituitary gland. In this study we have investigated the effects of neonatal estrogenic exposure upon the anterior pituitary. Both the early- and late-stage effects of exposure to a synthetic estrogenic agent, diethylstilbestrol (DES), upon pituitary gonadotroph cell function were assessed. We administered either a high dose (10 microg) or a low dose (0.1 microg) of DES to male rats during their neonatal period (P2-12). Gonadotroph function, cell number and morphology shortly after DES treatment (P18) and during adulthood (P90) were assessed. At P18 there was a significant decrease in follicle stimulating hormone (FSH) immunoreactivity in the pituitary gonadotroph cells in the high DES dose treated rats compared to control animals. No significant change in luteinizing hormone (LH) was observed at either DES dose. In adulthood (P90), there was no significant difference in FSH or LH gonadotroph immunoreactivity between control rats and any dose of DES-treated rats. Therefore, despite acute and selective ablation of FSH expression the gonadotrophs were able to recover in adulthood, suggesting that perinatal estrogenic exposure was only temporarily deleterious.

Estrogen-induced developmental disorders of the rat penis involve both estrogen receptor (ESR)- and androgen receptor (AR)-mediated pathways

This study tested the hypothesis that the estrogen receptor (ESR) pathway, androgen receptor (AR) pathway, or both mediate estrogen-induced developmental penile disorders. Rat pups received diethylstilbestrol (DES), with or without the ESR antagonist ICI 182,780 (ICI) or the AR agonist dihydrotestosterone (DHT) or testosterone (T), from Postnatal Days 1 to 6. Testicular T concentration, penile morphology and morphometry, and/or fertility was determined at age 7, 28, or 150 days. DES treatment alone caused 90% reduction in the neonatal intratesticular T surge; this reduction was prevented by ICI coadministration, but not by DHT or T coadministration. Unlike the T surge, coadministration of ICI and coadministration of DHT or T mitigated penile deformities and loss of fertility. Generally, ICI, DHT, or T treatment alone did not alter penile morphology; however, fertility was 20% that of controls in ICI-treated rats vs. 70%-90% in DHT- or T-treated rats. The lower fertility in the rats treated with ICI alone could be due to altered sexual behavior, as these males did not deposit vaginal plugs. In conclusion, observations that both an ESR antagonist and AR agonists prevent penile deformities and infertility suggest that both pathways are involved in estrogen-induced penile disorders. Observations that coadministration of ICI, but not DHT or T, prevents the DES-induced reduction in the neonatal T surge suggest that, although ICI exerts its mitigating effect both at the level of Leydig cells and penile stromal cells, DHT and T do so only at the level of stromal cells.

Recovery of suppressed male reproduction in mice exposed to progesterone during embryonic development by testosterone

The present study aimed to examine whether transplacental exposure to progesterone caused male reproductive abnormalities and whether the changes can be reversed after testosterone administration. Progesterone was injected to mice on day 1, 3, and 7 of pregnancy. The male pups (F1 generation) were allowed to grow for 50 days and assessed for reproductive performance. Gestational exposure to progesterone (7 mg/kg body weight) resulted in significant body weight gain with a decrease in reproductive tissue indices in mice. Total sperm count, viable sperm, and motile sperm decreased in experimental mice. Hypo-osmotic swelling test revealed that experimental mice sperm membrane integrity was severely altered. The activity levels of testicular steroidogenic marker enzymes (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B) and hydroxysteroid (17-beta) dehydrogenase 1 (HSD17B)) decreased significantly in mice exposed to progesterone during embryonic development when compared with the controls. The levels of serum testosterone decreased with an increase in serum FSH and LH in mice exposed to progesterone during embryonic development. Prenatal exposure to progesterone caused significant reduction in the number of spermatozoa and increase in the lumen of seminiferous tubule. The experimental mice that cohabited with normal females showed fertility reduction. Administration of testosterone (4.16 mg/kg body weight) on postnatal day 20, 30, and 40 to progesterone-exposed prenates resulted in recovery of progesterone-induced suppressed male reproduction. It is suggested that the impairment of male reproduction in mice exposed to progesterone during embryonic development could be mediated through the inhibition of testosterone production. These results also indicate thatin uteroexposure to progesterone affects male reproduction and that supplementation of testosterone restores the suppressed male reproduction.