Estrogen receptor alpha mediates estrogen-inducible abnormalities in the developing penis

The possible role of epigenetics in the etiology of hypospadias

INTRODUCTION

Hypospadias is a common malformation of the genitourinary system and is thought with a complex interplay between genetics and environmental factors likely contributing to its pathogenesis. This study aimed to investigate the receptor gene expressions of sex hormones, FGFR2, FGF8 and BMP7 and DNA methylations in these genes as an epigenetic mark, which may play a role in the etiology of hypospadias.

MATERIAL AND METHODS

The samples from the foreskin of 20 patients with hypospadias and 20 healthy children who underwent circumcision operations were collected. AR, ESR1, FGF8, FGFR2 and BMP7 gene expressions and DNA methylation rates of these genes were investigated in tissues.

RESULTS

While ESR1, FGFR2 and BMP7 gene expressions were found to be significantly higher in the hypospadias group, AR gene expression was found to be lower. In the hypospadias group, DNA methylation rates were found to be significantly higher in the ESR1, FGF8 and FGFR2 genes, but lower in the AR gene (Table).

DISCUSSION

Recent clinical studies suggest that epigenetic modifications may play a significant role in genital development, potentially contributing to the etiology of hypospadias. Our recent study demonstrated significant differences in foreskin AR, ESR1, and FGFR2 gene expression between patients with hypospadias and controls. To address this, the present study investigated DNA methylation levels of these same genes in hypospadias patients, hypothesizing that epigenetic modifications might be responsible for the observed gene expression changes. We again observed abnormalities in AR, ESR1, and FGFR2 gene expression in hypospadias patients. Furthermore, we found that DNA methylation patterns associated with these genes differed significantly between hypospadias and control groups.

CONCLUSIONS

Our study demonstrates significant alterations in DNA methylation of sex hormone receptor genes (ESR1 and AR), FGFR2, and FGF8, which correlate with abnormal expression of these genes in hypospadias cases. These findings suggest a potential role for epigenetic modifications in hypospadias etiology.

Estrogenic endocrine disruptor exposure directly impacts erectile function

Erectile dysfunction (ED) is an extremely prevalent condition which significantly impacts quality of life. The rapid increase of ED in recent decades suggests the existence of unidentified environmental risk factors contributing to this condition. Endocrine Disrupting Chemicals (EDCs) are one likely candidate, given that development and function of the erectile tissues are hormonally dependent. We use the estrogenic-EDC diethylstilbestrol (DES) to model how widespread estrogenic-EDC exposure may impact erectile function in humans. Here we show that male mice chronically exposed to DES exhibit abnormal contractility of the erectile tissue, indicative of ED. The treatment did not affect systemic testosterone production yet significantly increased estrogen receptor α (Esr1) expression in the primary erectile tissue, suggesting EDCs directly impact erectile function. In response, we isolated the erectile tissue from mice and briefly incubated them with the estrogenic-EDCs DES or genistein (a phytoestrogen). These acute-direct exposures similarly caused a significant reduction in erectile tissue contractility, again indicative of ED. Overall, these findings demonstrate a direct link between estrogenic EDCs and erectile dysfunction and show that both chronic and acute estrogenic exposures are likely risk factors for this condition.

A Genetics Study in the Foreskin of Boys with Hypospadias

Introduction

Hypospadias is a malformation of the genitourinary system in males, characterized by the placement of the urethral opening in the ventral surface of the penis. Although controversies continue about etiology, endocrine disrupting chemicals that disrupt normal endocrine signaling at the receptor or signal transduction level are thought to play an essential role in etiology. This study aimed to investigate the receptor gene expressions of the sex hormones and FGFR2, HOXA13, and TGFB1, which are considered to play an essential role in developing hypospadias.

Methods

The samples from the foreskin of 26 patients with hypospadias and 26 healthy children who underwent circumcision operations were collected. ESR1, AR, FGFR2, HOXA13, and TGFB gene expressions were investigated by real-time PCR in samples obtained during surgery.

Results

In the hypospadias group, ESR1 expression was increased (p = 0.013), and AR and FGFR2 expressions were decreased, which were found to be statistically significant (p = 0.027 and p = 0.003, respectively). There was no statistically significant difference between hypospadias and control groups in TGFBand HOXA13expression levels (p > 0.05).

Discussion

The results suggest that sex hormone receptors and FGFR2 may play an essential role in developing male external genital structures at the gene level. The defects in the expression of these genes can contribute to understanding the development of hypospadias.

Developmental and sexual dimorphic atlas of the prenatal mouse external genitalia at the single-cell level

Birth defects of the external genitalia are among the most common in the world. Proper formation of the external genitalia requires a highly orchestrated process that involves special cell populations and sexually dimorphic hormone signaling. It is clear what the end result of the sexually dimorphic development is (a penis in the male versus clitoris in the female); however, the cell populations involved in the process remain poorly defined. Here, we used single-cell messenger RNA sequencing in mouse embryos to uncover the dynamic changes in cell populations in the external genitalia during the critical morphogenetic window. We found that overall, male and female external genitalia are largely composed of the same core cellular components. At the bipotential stage of development (embryonic day or E14.5), few differences in cell populational composition exist between male and female. Although similar in cell population composition, genetic differences in key sexual differentiation developmental pathways arise between males and females by the early (E16.5) and late (E18.5) differentiation stages. These differences include discrete cell populations with distinct responsiveness to androgen and estrogen. By late sexual differentiation (E18.5), unique cell populations in both male and female genitalia become apparent and are enriched with androgen- and estrogen-responsive genes, respectively. These data provide insights into the morphogenesis of the external genitalia that could be used to understand diseases associated with defects in the external genitalia.

Etiology of Hypospadias: A Comparative Review of Genetic Factors and Developmental Processes Between Human and Animal Models

Hypospadias is a congenital anomaly of the penis with an occurrence of approximately 1 in 200 boys, but the etiology of the majority of hypospadias has remained unknown. Numerous genes have been reported as having variants in hypospadias patients, and many studies on genetic deletion of key genes in mouse genital development have also been published. Until now, no comparative analysis in the genes related literature has been reported. The basic knowledge of penile development and hypospadias is mainly obtained from animal model studies. Understanding of the differences and similarities between human and animal models is crucial for studies of hypospadias. In this review, mutations and polymorphisms of hypospadias-related genes have been compared between humans and mice, and differential genotype–phenotype relationships of certain genes between humans and mice have been discussed using the data available in PubMed and MGI online databases, and our analysis only revealed mutations in seven out of 43 human hypospadias related genes which have been reported to show similar phenotypes in mutant mice. The differences and similarities in the processes of penile development and hypospadias malformation among human and commonly used animal models suggest that the guinea pig may be a good model to study the mechanism of human penile development and etiology of hypospadias.

Uterine fibroids may play a protecting role against endometrial carcinoma in Chinese women with gynecological diseases

Background: It has been reported that uterine fibroids (UFs) may increase the risk of endometrial carcinoma (EC) with the underlying mechanism largely unknown. Here, we explore whether UF could be an influential factor for EC.

Methods: We have collected and analyzed clinical data from 4537 Chinese patients to study the co-incidence of UF and EC. Then, a large-scale literature-based data mining was conducted to identify genes implicated as UF downstream regulating targets and EC upstream regulators. In addition, a meta-analysis has been conducted for each of the EC-specific genes, using six independent UF expression datasets. The meta-analysis results, together with literature-based pathway analysis, were used to explore the potential explanation of the clinical data.

Results: Our results showed that the incidence rate of EC in the case of UF was 50.53% lower than without UF, which suggested a protective role of UF in EC patients. The meta-analysis identified three significantly overexpressed genes (HTRA3, HOPX, and PCNA) in the case of UF, which were implicated as EC inhibitors in the pathway analysis. Multiple linear regression (MLR) analysis showed that, compared with UF, aging might be a stronger influential factor for EC.

Conclusion: Among women with gynecological diseases, UFs may play a protecting role against EC in the Chinese population.

Prenatal masculinization of the auditory system in infants: The MIREC-ID study

Sex differences in inner-ear function are detectable in infants, notably through the measurement of otoacoustic emissions (OAEs). Prevailing theories posit that prenatal exposure to high levels of androgens in boys may weaken OAEs, and that this phenomenon may predominantly affect the right ear/left hemisphere (Geschwind-Galaburda (GG) hypothesis). Yet, actual tests of these models have been difficult to implement in humans. Here we examined the relationship between markers of fetal androgen exposure collected at birth (anogenital distances (AGD); penile length/width, areolar/scrotal/vulvar pigmentation) and at 6 months of age (2^nd to 4^th digit ratio (2D:4D)) with two types of OAEs, click-evoked OAEs (CEOAEs) and distortion-product OAEs (DPOAEs) (n = 49; 25 boys; 24 girls). We found that, in boys, scrotal pigmentation was inversely associated with the amplitude and reproducibility of CEOAEs in the right ear at 4 kHz, with trends also present in the same ear for mean CEOAE amplitude and CEOAE amplitude at 2 kHz. Penile length was inversely associated with the mean amplitude of DPOAEs in both the right and left ears, as well as with DPOAE amplitude in the right ear at 2 kHz and the reproducibility of CEOAEs in the left ear at 2.8 kHz. Finally, AGD-scrotum in boys was positively associated in boys with the amplitude of DPOAEs in the left ear at 2.8 kHz. Unexpectedly, there were no sex differences in the amplitude or reproducibility of OAEs, nor, in girls, any associations between androgenic markers and auditory function. Nonetheless, these findings, reported for the first time in a sample of human infants, support both the prenatal-androgen-exposure and GG models as explanations for the masculinization of auditory function in male infants.

Adipocyte accumulation in corpus cavernosum: First clinical evidence and pathophysiological implications in erectile dysfunction

OBJECTIVES

Animal models have shown that erectile dysfunction is associated with adipocyte accumulation under tunica albugínea, which could be involved in venous leakage and loss of penile rigidity. In the current sudy, we compared the histology of the penile sub-albuginean region of drug-refractory erectile dysfunction patients undergoing penile prosthesis implantation with potent patients with Peyronie's disease undergoing curvature correction procedures.

MATERIALS AND METHODS

Seventeen refractory erectile dysfunction patients and fourteen potent patients with Peyronie's disease were recruited. Sub-albuginean tissue samples were taken in each surgery. An expert uropathologist analysed each section. A bivariate analysis was performed. Multivariate logistic regression was used to calculate adjusted odds ratios; P value<.05 was considered significant.

RESULTS

Eleven patients (11/17) in the case group presented cavernous fat cell accumulation, while only one patient (1/14) in the control group presented this finding (P<.05). Adjusted odds ratio for erectile dysfunction was 40.72; 95% CI 2.28-727.29 (P=.012).

CONCLUSIONS

Different studies have shown that androgen disruption could be involved in penile structural changes, leading to trabecular smooth muscle apoptosis and trans or de-differentiation into adipocytes. This is the first prospective study in humans to report an association between erectile dysfunction and sub-albuginean adipocyte accumulation. Venous leakage secondary to this phenomenon could be a factor in the pathophysiology of erectile dysfunction, especially in patients that do not respond to medical therapy.

Timing of androgen receptor disruption and estrogen exposure underlies a spectrum of congenital penile anomalies

Congenital penile anomalies (CPAs) are among the most common human birth defects. Reports of CPAs, which include hypospadias, chordee, micropenis, and ambiguous genitalia, have risen sharply in recent decades, but the causes of these malformations are rarely identified. Both genetic anomalies and environmental factors, such as antiandrogenic and estrogenic endocrine disrupting chemicals (EDCs), are suspected to cause CPAs; however, little is known about the temporal window(s) of sensitivity to EDCs, or the tissue-specific roles and downstream targets of the androgen receptor (AR) in external genitalia. Here, we show that the full spectrum of CPAs can be produced by disrupting AR at different developmental stages and in specific cell types in the mouse genital tubercle. Inactivation of AR during a narrow window of prenatal development results in hypospadias and chordee, whereas earlier disruptions cause ambiguous genitalia and later disruptions cause micropenis. The neonatal phase of penile development is controlled by the balance of AR to estrogen receptor α (ERα) activity; either inhibition of androgen or augmentation of estrogen signaling can induce micropenis. AR and ERα have opposite effects on cell division, apoptosis, and regulation of Hedgehog, fibroblast growth factor, bone morphogenetic protein, and Wnt signaling in the genital tubercle. We identify Indian hedgehog (Ihh) as a novel downstream target of AR in external genitalia and show that conditional deletion of Ihh inhibits penile masculinization. These studies reveal previously unidentified cellular and molecular mechanisms by which antiandrogenic and estrogenic signals induce penile malformations and demonstrate that the timing of endocrine disruption can determine the type of CPA.

Genetic polymorphisms in ESR1 and ESR2 genes, and risk of hypospadias in a multiethnic study population

PURPOSE

Estrogenic endocrine disruptors acting via estrogen receptors α (ESR1) and β (ESR2) have been implicated in the etiology of hypospadias, a common congenital malformation of the male external genitalia. We determined the association of single nucleotide polymorphisms in ESR1 and ESR2 genes with hypospadias in a racially/ethnically diverse study population of California births.

MATERIALS AND METHODS

We investigated the relationship between hypospadias and 108 ESR1 and 36 ESR2 single nucleotide polymorphisms in 647 cases and 877 population based nonmalformed controls among infants born in selected California counties from 1990 to 2003. Subgroup analyses were performed by race/ethnicity (nonHispanic white and Hispanic subjects) and by hypospadias severity (mild to moderate and severe).

RESULTS

Odds ratios for 33 of the 108 ESR1 single nucleotide polymorphisms had p values less than 0.05 (p = 0.05 to 0.007) for risk of hypospadias. However, none of the 36 ESR2 single nucleotide polymorphisms was significantly associated. In stratified analyses the association results were consistent by disease severity but different sets of single nucleotide polymorphisms were significantly associated with hypospadias in nonHispanic white and Hispanic subjects. Due to high linkage disequilibrium across the single nucleotide polymorphisms, haplotype analyses were conducted and identified 6 haplotype blocks in ESR1 gene that had haplotypes significantly associated with an increased risk of hypospadias (OR 1.3 to 1.8, p = 0.04 to 0.00001). Similar to single nucleotide polymorphism analysis, different ESR1 haplotypes were associated with risk of hypospadias in nonHispanic white and Hispanic subjects. No significant haplotype association was observed for ESR2.

CONCLUSIONS

The data provide evidence that ESR1 single nucleotide polymorphisms and haplotypes influence the risk of hypospadias in white and Hispanic subjects, and warrant further examination in other study populations.

Increased gene copy number of VAMP7 disrupts human male urogenital development through altered estrogen action

Vesicle transport is intimately connected with key nuclear functions and transcriptional regulation. Here, children born with congenital genitourinary tract masculinization disorders were analyzed by array-Comparative Genomic Hybridization, which revealed the presence of de novo copy number gains on Xq28 encompassing the VAMP7 gene encoding a vesicle-trafficking protein. Humanized VAMP7 BAC transgenic mice displayed cryptorchidism, urethral defects, and hypospadias. Mutant mice exhibited reduced penile length, focal spermatogenic anomalies, diminished sperm motility, and subfertility. VAMP7 colocalized with estrogen receptor alpha (ESR1) in the presence of ligand. Elevated levels of VAMP7 markedly intensified ESR1 transcriptional activity by increasing ESR1 protein cellular content upon ligand stimulation and up-regulated the expression of estrogen-responsive genes including ATF3, CYR61, and CTGF, all of which are implicated in human hypospadias. Hence, increased gene dosage of the SNARE protein, VAMP7, enhances estrogen receptor action in male genitourinary tissues, affects the virilization of the reproductive tract, and results in genitourinary birth defects in humans.

Estrogen-induced maldevelopment of the penis involves down-regulation of myosin heavy chain 11 (MYH11) expression, a biomarker for smooth muscle cell differentiation

Cavernous smooth muscle cells are essential components in penile erection. In this study, we investigated effects of estrogen exposure on biomarkers for smooth muscle cell differentiation in the penis. Neonatal rats received diethylstilbestrol (DES), with or without the estrogen receptor (ESR) antagonist ICI 182,780 (ICI) or the androgen receptor (AR) agonist dihydrotestosterone (DHT), from Postnatal Days 1 to 6. Tissues were collected at 7, 10, or 21 days of age. The smooth muscle cell biomarker MYH11 was studied in depth because microarray data showed it was significantly down-regulated, along with other biomarkers, in DES treatment. Quantitative real time-PCR and Western blot analyses showed 50%-80% reduction (P ≤ 0.05) in Myh11 expression in DES-treated rats compared to that in controls; and ICI and DHT coadministration mitigated the decrease. Temporally, from 7 to 21 days of age, Myh11 expression was onefold increased (P ≥ 0.05) in DES-treated rats versus threefold increased (P ≤ 0.001) in controls, implying the long-lasting inhibitory effect of DES on smooth muscle cell differentiation. Immunohistochemical localization of smooth muscle alpha actin, another biomarker for smooth muscle cell differentiation, showed fewer cavernous smooth muscle cells in DES-treated animals than in controls. Additionally, DES treatment significantly up-regulated Esr1 mRNA expression and suppressed the neonatal testosterone surge by 90%, which was mitigated by ICI coadministration but not by DHT coadministration. Collectively, results provided evidence that DES treatment in neonatal rats inhibited cavernous smooth muscle cell differentiation, as shown by down-regulation of MYH11 expression at the mRNA and protein levels and by reduced immunohistochemical staining of smooth muscle alpha actin. Both the ESR and the AR pathways probably mediate this effect.

Exposure of neonatal rats to anti-androgens induces penile mal-developments and infertility comparable to those induced by oestrogens

We previously reported that oestrogen exposure in neonatal rats induced permanent infertility and malformed penis characterized by fat accumulation, which replaced most of the smooth muscle cells and cavernous spaces in the body of the penis, structures essential for erection. The objective of this study was to determine if reduced androgen production/action in the neonatal period, in the absence of exogenous oestrogen exposure, induces penile deformities similar to those caused by oestrogen. Male rats were treated from postnatal days 1-6 with GnRH antagonist antide (A, 10 mg/kg) or androgen receptor (AR) antagonist flutamide (F, 50 mg/kg) or F + A, with or without AR agonist dihydrotestosterone (DHT, 20 mg/kg). For comparison, pups received diethylstilbestrol (DES, 0.1 mg/kg), with or without DHT. Tissues were collected at ages 7 and 12 days and at adulthood. Flutamide alone decreased penile length and weight significantly (p < 0.05), but it caused neither fat accumulation, nor affected fertility (80% vs. 87% in controls). Antide alone reduced penile length and weight significantly, and induced fat accumulation in 4/11 rats and infertility in 13/14 rats. Conversely, all 11 F + A-treated rats, similar to all nine DES-treated rats, had fat accumulation and loss of smooth muscle cells and cavernous spaces in the body of the penis and were infertile. In addition, reductions in penile length and weight were higher than in rats treated with F or A alone. DHT co-administration mitigated penile deformities in the DES group, but did not in the F + A group. Testicular testosterone was reduced by 70-95% at 7 or 12 days of age in all treated groups, except in the F group, which had threefold higher testosterone than controls. Collectively, data unequivocally show that reduced androgen production/action in the neonatal period, in the absence of oestrogen exposure, induces permanent infertility and malformed penis similar to that caused by oestrogen.

Molecular mechanisms of induction of persistent changes by estrogenic chemicals on female reproductive tracts and external genitalia

The effects of environmental endocrine-disrupting chemicals (EDCs) are a great and growing concern for human and animal development and life. The reproductive organs are considered as a primary target of EDCs, yet the effects on reproductive organs can extend to other body systems. Perinatal diethylstilbestrol (DES)-exposed mice exhibit various reproductive organ abnormalities. The perinatal DES-exposure model has allowed insight into our understanding of the mechanisms of persistent reproductive organ abnormalities elicited by exposure to estrogens and/or estrogenic EDCs. The persistent changes in the vagina of neonatally DES-exposed mice result from sustained expression of growth factors by ligand-independent transcriptional activation of the estrogen receptor. Developmental regulatory genes, such as Wnt and Hox genes, are also targets of DES during fetal stages and altered gene expression can induce malformations of the reproductive organs. In this review, we focus on the development of female reproductive tracts and external genitalia, and discuss the recent progress in understanding the disruptive effects of estrogens and EDCs on these organs.

ZEB1 is estrogen responsive in vitro in human foreskin cells and is over expressed in penile skin in patients with severe hypospadias

PURPOSE

We determined the effect of estrogen on ZEB1 in vitro and tested the hypothesis that ZEB1 is over expressed in the penile skin of subjects with hypospadias.

MATERIALS AND METHODS

Hs68 cells, a fibroblast cell line derived from human foreskin, were exposed to 0, 1, 10 and 100 nM estrogen, and the expression level of ZEB1 was assessed using reverse transcription real-time polymerase chain reaction, Western blot and immunocytochemical analysis. Next, preputial skin was prospectively collected from case and control subjects at hypospadias repair (37 cases) and circumcision (11). Hypospadias was classified as severe (13 cases) or mild (24) based on the position of the urethral meatus. ZEB1 expression was quantified using reverse transcription real-time polymerase chain reaction, Western blot and immunohistochemical analysis.

RESULTS

Estrogen increased ZEB1 expression at the mRNA and protein levels in Hs68 cells in a concentration dependent fashion (p <0.01). Subjects with severe hypospadias had significantly higher ZEB1 mRNA levels and protein expression compared to controls or subjects with mild hypospadias (both p <0.01). Subjects with severe hypospadias had increased expression of ZEB1 in the basal layers of the preputial epidermis.

CONCLUSIONS

Estrogen increases ZEB1 expression in a human foreskin fibroblast cell line in vitro. Furthermore, ZEB1 is significantly over expressed in the penile skin of subjects with severe hypospadias. We propose that ZEB1 overexpression may contribute to development of hypospadias and may mediate the effect of estrogen on developing external male genitalia.

Genetically induced estrogen receptor α mRNA (Esr1) overexpression does not adversely affect fertility or penile development in male mice

Previously, we reported that estrogen receptor α mRNA (Esr1) or protein (ESR1) overexpression resulting from neonatal exposure to estrogens in rats was associated with infertility and maldeveloped penis characterized by reduced length and weight and abnormal accumulation of fat cells. The objective of this study was to determine if mutant male mice overexpressing Esr1 are naturally infertile or have reduced fertility and/or develop abnormal penis. The fertility parameters, including fertility and fecundity indices, numbers of days from the day of cohabitation to the day of delivery, and numbers of pups per female, were not altered from controls as a result of Esr1 overexpression. Likewise, penile morphology, including the length, weight, and diameter and os penis development, was not altered from controls. Conversely, weights of the seminal vesicles and bulbospongiosus and levator ani (BS/LA) muscles were significantly (P < .05) lower as compared with controls; however, the weight of the testis, the morphology of the testis and epididymis, and the plasma and testicular testosterone concentration were not different from controls. Hence, genetically induced Esr1 overexpression alone, without an exogenous estrogen exposure during the neonatal period, is unable to adversely affect the development of the penis as well as other male reproductive organs, except for limited, but significant, reductions in weights of the seminal vesicles and BS/LA muscles.

Mechanisms of obesity-induced male infertility

Male infertility, characterized by hypogonadism, decreased semen quality or ejaculatory dysfunction, accounts for approximately 20% of infertility cases. Obesity and metabolic dysfunction have been identified, among other causal factors, to contribute to male infertility. In the context of the Western world's 'obesity epidemic', this article discusses three main biological mechanisms linking obesity to impaired male reproductive function: hypogonadism, testicular heat stress/hypoxia-induced apoptosis and endocrine disruption by 'obesogens'. Among these, obesity-induced hypogonadism is undoubtedly the most clinically significant and is easily assessed. Rapidly expanding areas of research in this area include leptin modulation of kisspeptins and hypothalamic-pituitary-testicular hormone pathways, and roles of other adipocytokines in male infertility, as well as the impact of exposure to obesogens on the quality of semen.

Normal morphology and hormone receptor expression in the male California sea lion (Zalophus californianus) genital tract

Histomorphology and estrogen alpha (ER alpha), and progesterone receptor (PR) expression were evaluated in free-ranging stranded male California sea lions (Zalophus californianus). Hormone receptor expression was evaluated using an immunohistochemical technique with monoclonal antibodies. Estrogen and PRs were identified in the efferent ductules, prostate gland, corpus cavernosa, corpus spongiosium, penile urethra, and in the epithelium and stroma of both the penis and prepuce. In some tissues, ER alpha expression was more intense in the stroma, emphasizing the importance of the stroma in hormone-mediated growth and differentiation of reproductive organs. To our knowledge, this is the first study to localize ER alpha and PR to the epithelium of the glans penis. The results of this investigation add to the general knowledge of male California sea lion reproduction and suggest that estrogens could have a role in the function of the male reproductive tract.

Mal-development of the penis and loss of fertility in male rats treated neonatally with female contraceptive 17alpha-ethinyl estradiol: a dose-response study and a comparative study with a known estrogenic teratogen diethylstilbestrol

The objectives of this study were to find a minimal dose of 17alpha-ethinyl estradiol (EE) that is detrimental to the developing penis and fertility and to compare estrogenic effects between EE and diethylstilbestrol (DES). Neonatal rats received EE at 10 ng (1 microg/kg), 100 ng, 1 microg, or 10 microg per pup on alternate days from postnatal days 1 to 11 (dose-response study) or received EE or DES at 100 ng per pup daily from postnatal days 1 to 6 (comparative study). Effects of EE were dose dependent, with > or = 100-ng dose inducing significant (p < 0.05) reductions in penile length, weight, and diameter. Additionally, the penis was malformed, characterized by underdeveloped os penis and accumulation of fat cells. Fertility was 0% in the > or = 1-microg groups, in contrast to 60% in the 100-ng group and 100% in the 10-ng and control groups. Animals treated with > or = 10 ng had significant reductions in the weight of bulbospongious muscle, testis, seminal vesicle, epididymal fat pad, and in epididymal sperm numbers. A comparison of EE and DES effects showed similar reductions in penile weight and length and the weight of bulbospongiosus muscle, testis, seminal vesicle, epididymis, and epididymal fat pad in both adolescent and adult rats. While 5/6 control males sired, only 1/6 in the EE group and 0/6 in the DES group sired. Hence, neonatal exposure to EE at 10 ng (environmentally relevant dose) adversely affects male reproductive organs. A dose ten times higher than this leads to permanently mal-developed penis and infertility. Furthermore, EE and DES exposures show similar level of toxicity to male reproductive organs.

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.

Role of estrogen in induction of penile dysmorphogenesis: a review

In this review, we report permanent dysmorphogenesis of the penis and loss of fertility in adult rats treated neonatally with estrogen. Specifically, we report replacement of smooth muscle cells and cavernous spaces by fat cells in the corpus cavernosum penis, but not in the adjoining corpus spongiosum. Induction of these novel, region-specific phenotypes is dose-dependent, requires a critical window of exposure and associated with decreased testosterone and up-regulation of estrogen receptor α (ERα). The resistance of ERα knockout mice to develop these abnormalities implies an unequivocal role for ERα in mediating maldevelopment of the penis. Additionally, the prevention of estrogen-inducible penile abnormalities by ER antagonist ICI 182 780 implies that a functional ER-mediated pathway is essential for inducing penile abnormalities. Likewise, the ability of testosterone or dihydrotestosterone to negate these abnormalities suggests a role for an androgen receptor (AR)-mediated pathway. Taken together, these observations led us to hypothesize that neonatal estrogen exposure, via an ER-mediated pathway (direct action) or an AR-mediated pathway (indirect action through decreased testosterone) or both pathways, up-regulates ERα expression in stromal cells of the penis, which are then reprogrammed such that their differentiation into smooth muscle cells is inhibited and their differentiation into adipocytes is stimulated.