Estrogens and epididymal function

How does the boar epididymis regulate the emission of fertile spermatozoa?

The epididymis is responsible for peripheral immune tolerance of maturing spermatozoa even though these have xeno-antigens foreign to the male and female immune system. The epididymis also produces factors required for fertilization and serves as a sperm repository until the time of ejaculation. These reproduction-relevant epididymal functions occur in the mesonephros-derived duct-system that is composed of absorptive and secretory epithelial cells with the capacity for merocrine and apocrine secretion of proteins, antioxidative- and electrolyte/pH-regulating enzymes and small, non-coding RNAs (sncRNAs), many stored in epididymosomes for sperm adhesion and long-lasting modifications of sperm functions. This paper provides a review summary of current and new knowledge of how the boar epididymis affects the quality of spermatozoa in the ejaculate of breeding boars. There is a particular focus on sperm maturation, survival, function and the role of signaling to the female immune system in fertility modulation. Furthermore, aspects related to the ductus epithelial contributions regarding electrolyte control, protein production, release of epididymosomes that contain sncRNAs are emphasized as are novel associations with fertility of the male, sperm quiescence during storage in the cauda epididymis, and on changes occurring in sperm subsequent to ejaculation.

Effect of heavy metals on epididymal morphology and function: An integrative review

Male fertility has deteriorated over the last decades, and environmental risk factors are among the possible causes of this phenomenon. Pollutants such as heavy metals might accumulate in male reproductive organs to levels that are associated with reproductive disorders. Several studies reported detrimental effects of inorganic arsenic (iAs⁺³/iAs⁺⁵), cadmium (Cd⁺²), lead (Pb⁺²), and mercury (Hg⁺²/CH₃Hg⁺²) on the epididymis, which plays a crucial role in sperm maturation. However, the magnitude of their effects and the consequences on the physiology of the epididymis are still unclear. Therefore, an integrative review with meta-analyses was conducted examining 138 studies to determine how exposure to arsenic, cadmium, lead, and mercury affects epididymal morphology and functions, using primarily murine data from experimental studies as a source. This study showed that exposure to metal(loids) reduced epididymal weight, sperm motility, and sperm number. Inorganic arsenic, cadmium, and lead damaged sperm structures within the epididymal duct. While sodium arsenite, sodium arsenate, and lead acetate generate oxidative stress by an imbalance between ROS production and scavenging, cadmium chloride causes an increase in the pH level of the luminal fluid (from 6.5 to 7.37) that diminishes sperm viability. Inorganic arsenic induced a delay in the sperm transit time by modulating noradrenaline and dopamine secretion. Subacute exposure to heavy metals at concentrations < 0.1 mg L^-1 initiates a dyshomeostasis of calcium, copper, iron, and zinc that disturbs sperm parameters and reduces epididymal weight. These alterations worsen with prolonged exposure time and higher doses. Most studies evaluated the effects of concentrations > 1.1 mg L^-1 of heavy metals on the epididymis rather than doses with relevant importance for human health risk. This meta-analytical study faced limitations regarding a deeper analysis of epididymis physiology. Hence, several recommendations for future investigations are provided. This review creates a baseline for the comprehension of epididymal toxicology.

Essential Roles of Efferent Duct Multicilia in Male Fertility

Cilia are microtubule-based hair-like organelles on the cell surface. Cilia have been implicated in various biological processes ranging from mechanosensation to fluid movement. Ciliary dysfunction leads to a plethora of human diseases, known as ciliopathies. Although non-motile primary cilia are ubiquitous, motile multicilia are found in restricted locations of the body, such as the respiratory tract, the oviduct, the efferent duct, and the brain ventricles. Multicilia beat in a whip-like motion to generate fluid flow over the apical surface of an epithelium. The concerted ciliary motion provides the driving force critical for clearing airway mucus and debris, transporting ova from the ovary to the uterus, maintaining sperm in suspension, and circulating cerebrospinal fluid in the brain. In the male reproductive tract, multiciliated cells (MCCs) were first described in the mid-1800s, but their importance in male fertility remained elusive until recently. MCCs exist in the efferent ducts, which are small, highly convoluted tubules that connect the testis to the epididymis and play an essential role in male fertility. In this review, we will introduce multiciliogenesis, discuss mouse models of male infertility with defective multicilia, and summarize our current knowledge on the biological function of multicilia in the male reproductive tract.

Effects of shikonin on the development of ovarian follicles and female germline stem cells

Objective

To investigate the effects and potential mechanism of action of shikonin (SHK) on the development of ovarian follicles and female germline stem cells (FGSCs).

Methods

Female Kunming adult mice were administered SHK (0, 20 and 50 mg/kg) by oral gavage. Cultures of FGSCs were treated with SHK 32 μmol/l for 24 h. The ovarian index in mouse ovaries was calculated. Numbers of primordial, primary and atretic follicles were counted. Germline stem cell markers and apoptosis were examined. Levels of glutathione (GSH), superoxide dismutase (SOD) and reactive oxygen species (ROS) were measured.

Results

Both doses of SHK significantly decreased the ovarian index, the numbers of primordial follicles, primary follicles and antral follicles in mice. SHK significantly increased the numbers of atretic follicles and atretic corpora lutea. SHK promoted apoptosis in vivo and in vitro. SHK significantly decreased the levels of the germline stem cell markers. SHK significantly lowered GSH levels and the activity of SOD in the peripheral blood from mice, whereas SHK significantly elevated cellular ROS content in FGSCs.

Conclusions

These current results suggested that follicular development and FGSCs were suppressed by SHK through the induction of apoptosis and oxidative stress might be involved in this pathological process.

Dose-related morphological changes in the epididymal region of sexually active adult male Japanese quail treated with di-n-butyl phthalate (DBP) commencing during the pre-pubertal stage

Di-n-butyl phthalate (DBP) is widely used as a plasticizer in personal care and medical products and is known to induce toxicity in the male reproductive organs in both mammals and birds. In this study, there was investigation of the effects of DBP on the epithelium of the rete testis, proximal, and distal efferent ductules and epididymal duct of adult Japanese quail (Coturnix japonica) following treatment with varying doses during the pre-pubertal and peri-pubertal periods. Pre-pubertal quail (n = 25) 4 weeks post-hatching were dosed orally with 10, 50, 200 and 400 mg DBP/kg/d, for 30 days and control birds were administered corn-oil only (n = 5 per group). Histo-metrically, there was lesser (P <  0.001) epithelial heights of the rete testis and efferent ductules in all quail DBP-treated groups, but not in the epididymal duct epithelium. There were no morphological change effects as a result of DBP treatments in the rete testis epithelium, while there were epithelial cytoplasmic vacuoles detected in the distal efferent ductule and epididymal duct of birds treated with 50, 200 and 400 mg DPB/kg/d. There were several lesions, including degenerative changes, cytoplasmic vacuoles, apoptosis and autophagy in the epithelium of the proximal efferent ductule in quail treated with 200 and 400 mg DBP/kg/d. Overall, the results indicate that treatment with DBP during the pre-pubertal period induced dose-dependent histometric and morphological changes in the epithelium of the epididymal region. It is concluded that the proximal efferent ductule was a highly sensitive component of the epididymal tissues of Japanese quail following treatment with DBP during the pre-pubertal period.

Changes in nitric oxide, carbon monoxide, hydrogen sulfide and male reproductive hormones in response to chronic restraint stress in rats

Gasotrasmitters are endogenously synthesized gaseous molecules that are engaged in cellular physiological and pathological processes. Stress influences various physiological aspects of an organism and amends a normal system's functions, including those of the reproductive system. This study aims to investigate the effect of long-term exposure to restraint stress on the male reproductive system as well as the possible impact of stress on the levels of nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S), and the expression of their producing-enzymes. In this study, rats were subjected to the restraint condition for 2 h per day and 7 days per week for 8 consecutive weeks. The results revealed decreases in the serum levels of kisspeptin-1(Kiss-1), gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and dehydroepiandrosterone sulfate (DHEA-s); however, corticosterone, gonadotropin-inhibitory hormone (GnIH), estradiol (E2) and prolactin levels increased following restraint stress. The mRNA expression levels of NO synthases (NOSs); neuronal NOS (nNOS), inducible NOS (iNOS) and H₂S synthases; cystathionine-γ-lyase- (CSE), 3-mercaptopyruvate-sulfurtransferase- (3MST) and CO-producing enzyme; heme oxygenase-2 (HO-2) were upregulated in the hypothalamus of restraint rats. Testicular mRNA expression levels of endothelial NOS (eNOS), nNOS, HO-1 and HO-2 were upregulated whereas cystathionine β-synthase (CBS), CSE and 3MST expression levels were downregulated following restraint stress. Concentrations of NO increased in the testes but decreased in the semen of restraint rats. On the contrary, CO levels were reduced in the testes while they were elevated in the semen, whereas H₂S concentrations decreased in both testes and semen of restraint rats. Concentrations of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), as well as total antioxidant capacity (TAC) rose in the testes, while they declined in the semen of the restraint group. Restraint stress decreases the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the testes while increasing them in the semen. Collectively, restraint stress negatively impacts male reproductive functions and modulates gasotransmitters producing-enzymes expression in the hypothalamus and testes.

Modification of genital kidney nephrons for sperm transport in a plethodontid salamander, Eurycea longicauda

Salamanders possess kidneys with two distinct regions: a caudal pelvic portion and cranial genital portion. Nephrons of the pelvic region are responsible for urine formation and transport. Nephrons of the genital region transport sperm from testes to Wolffian ducts; however, nephrons of the genital region possess all the same functional regions found in pelvic kidney nephrons that are involved with urine formation and transport (renal corpuscles, proximal tubules, distal tubules, and collecting ducts). Morphological similarities between pelvic and genital regions stimulated past researchers to hypothesize that nephrons of genital kidneys possess dual function; that is, sperm transport and urine formation/transport. Considering size of glomeruli is directly related to the total amount of blood plasma filtered into the Bowman's space, we tested the hypothesis that nephrons of genital kidneys have reduced urine formation function by comparing glomerular size between nephrons of pelvic and genital kidney regions in Eurycea longicauda with general histological techniques. Light microscopy analysis revealed that glomeruli of pelvic kidneys were significantly larger than those measured from genital kidneys. Transmission electron microscopy analysis also revealed modifications in genital kidney nephrons when compared to pelvic kidney nephrons that suggested a decrease in urine formation function in genital kidneys. Such modifications included a decrease in basal and lateral plasma membrane folding in genital kidney proximal and distal tubules compared to that of pelvic kidney proximal and distal tubules. Genital kidney proximal tubules were also ciliated, which was not observed in pelvic kidney proximal tubules. In conclusion, although structurally similar at the histological level, it appears that nephrons of genital kidneys have decreased urine formation function based on glomerular size comparison and nephron ultrastructure.

Differences in aromatase expression and steroid hormone concentrations in the reproductive tissues of male domestic turkeys (Meleagris gallopavo) with white and yellow semen

1. To show hormonal differences between male turkeys with yellow semen syndrome (YSS) and white, normal semen (WNS), the expression of aromatase, oestrogen receptor α (ERα), and oestrogen receptor β (ERβ) as well as testosterone and oestradiol concentrations in YSS and WNS testes, epididymis, and ductus deferens were examined. 2. To measure gene expression levels of aromatase and oestrogen receptors (ERs), three complementary techniques (real-time PCR, Western blot, and immunohistochemistry) were used, whereas steroid hormone levels were determined radio-immunologically. 3. Upregulation of aromatase and ERα mRNAs in YSS testes (P < 0.05; P < 0.01), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.05; P < 0.01) compared to those of WNS tissues was detected. Significant increases in the levels of aromatase and ERα proteins were detected in YSS testes (P < 0.001; P < 0.05), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.001; P < 0.05). The expression of ERβ mRNA and protein level was upregulated in the testes (P < 0.05; P < 0.01) and epididymis (P < 0.001; P < 0.01) but not in ductus deferens where it was downregulated (P < 0.01; P < 0.01). Increased intensity of immunoreactive proteins in YSS versus WNS reproductive tissues corroborated gene expression results. 4. Testosterone concentration diminished in YSS epididymis (P < 0.05) and ductus deferens (P < 0.05), but not in the testes, remaining at high level (P < 0.05) compared to WNS values. Concomitantly, increased oestradiol concentration was found in YSS testes (P < 0.05) and epididymis (P < 0.05) but decreased in the ductus deferens (P < 0.05). 5. From the published literature, this study is the first to demonstrate the ability for androgen aromatisation in the turkey reproductive tissues and to show the cellular targets for locally produced oestrogens. The data suggested that the androgen/oestrogen ratio is a mechanistic basis for amplification of differences between turkeys with white and yellow semen and that these results can have a relevance in applied sciences to widen the knowledge on domestic bird reproduction.

Colocalization of metastasis-associated proteins 1/2 and estrogen receptor alpha in rat epididymis

It has been suggested that metastasis-associated proteins 1 and 2 (MTA1 and MTA2) are capable of suppressing estrogen receptor alpha (ERα) transactivation activity in breast cancer cells. ERα, which is present in the epididymis, is a crucial mediator of maintaining the luminal environment necessary for proper sperm maturation and function. The present study was undertaken to analyze the expression profile of both MTA1 and MTA2 in the epididymis of rats and to ascertain whether MTA1/2 colocalizes with ERα in the epididymis and primary cultured epididymal epithelial cells. Reverse transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry analyses were utilized to demonstrate that MTA1 and MTA2 are expressed in the epididymis. Furthermore, these analyses revealed that MTA1 and MTA2 are predominantly localized in the nuclei of almost all epididymal epithelial cells. Immunofluorescence staining revealed that MTA1/2 colocalizes with ERα in epididymal epithelial cells. In conclusion, MTA1 and MTA2 are expressed in the epididymis of rats; these proteins colocalize with ERα in epididymal epithelial cells, suggesting that MTA1 and MTA2 may be involved in the regulation of ERα transactivation activity in the epididymis of rats to facilitate a stable environment in the lumen.

Estrogen receptor ESR1 mediates activation of ERK1/2, CREB, and ELK1 in the corpus of the epididymis

Expression of the estrogen receptor ESR1 is higher in the corpus than it is in the initial segment/caput and cauda of the epididymis. ESR1 immunostaining in the corpus has been localized not only in the nuclei but also in the cytoplasm and apical membrane, which indicates that ESR1 plays a role in membrane-initiated signaling. The present study investigated whether ESR1 mediates the activation of rapid signaling pathways by estradiol (E2) in the epididymis. We investigated the effect of E2 and the ESR1-selective agonist (4,4',4''-(4-propyl-(1H)-pyrazole-1,3,5-triyl)trisphenol (PPT) on the activation of extracellular signal-regulated protein kinases (ERK1/2), CREB protein, and ETS oncogene-related protein (ELK1). Treatment with PPT did not affect ERK1/2 phosphorylation in the cauda, but it rapidly increased ERK1/2 phosphorylation in the initial segment/caput and corpus of the epididymis. PPT also activated CREB and ELK1 in the corpus of the epididymis. The PPT-induced phosphorylation of ERK1/2, CREB, and ELK1 was blocked by the ESR1-selective antagonist MPP and by pretreatment with a non-receptor tyrosine kinase SRC inhibitor, an EGFR kinase inhibitor, an MEK1/2 inhibitor, and a phosphatidylinositol-3-kinase inhibitor. In conclusion, these results indicate that the corpus, which is a region with high expression of the estrogen receptor ESR1, is a major target in the epididymis for the activation of rapid signaling by E2. The sequence of events that follow E2 interaction with ESR1 includes the SRC-mediated transactivation of EGFR and the phosphorylation of ERK1/2, CREB, and ELK1. This rapid estrogen signaling may modulate gene expression in the corpus of the epididymis, and it may play a role in the dynamic microenvironment of the epididymal lumen.

Steroid regulation of early postnatal development in the corpus epididymidis of pigs

Development of the epididymis including blood-epididymal barrier formation is not required until sperm reach the epididymis peripuberally. Regulation of this development in the early postnatal period is largely unknown. The current objectives were to evaluate potential roles of endogenous estrogen and androgen signaling during early development of the corpus epididymidis and to determine the timing of formation of the blood-epididymal barrier in the pig. Effects of endogenous steroids were evaluated using littermates treated with vehicle, an aromatase inhibitor (letrozole) to reduce endogenous estrogens, an estrogen receptor antagonist (fulvestrant) or an androgen receptor antagonist (flutamide). Phosphorylated histone 3 immunohistochemistry was used to identify proliferating epithelial cells. Lanthanum nitrate and electron microscopy were used to analyze formation of the blood barrier in the corpus epididymidis. Reducing endogenous estrogens increased the number of proliferating corpus epithelial cells at 6 and 6.5 weeks of age compared with vehicle-treated boars (P<0.01 and P<0.001 respectively). Blocking androgen receptors did not alter proliferation rate at 6.5 weeks of age. Although barrier formation was similar between 6 and 6.5 weeks of age in vehicle-treated animals, intercellular barriers increased in letrozole-treated littermates at 6.5 weeks of age. Fulvestrant treatment, which should mimic aromatase inhibition for regulation through ESR1 and ESR2 signaling but potentially stimulate endogenous estrogen signaling through the G protein-coupled estrogen receptor (GPER), had the opposite effect on aromatase inhibition. These responses in conjunction with the presence of GPER in the corpus epididymidis suggest early corpus epididymal development is regulated partially by GPER.

Relationship between testicular lesion and hormone levels in male rats infected with Trypanosoma evansi

The aim of this study was to evaluate the relationship between testicular lesions and hormone levels in rats experimentally infected with Trypanosoma evansi. For that, the measurement of reproductive hormones, histopathology and biomarkers of cellular injury were carried out in twenty-four animals, which were divided into two groups with 12 animals each. Group A was the negative control, or uninfected, while group B was composed by animals infected with T. evansi. Both groups were divided again into two other subgroups (n=6), from which serum and testicular fragments were collected on days 5 (A1 and B1) and 15 (A2 and B2) post-infection (PI). The morphological analysis showed increased alterations of head and tail of sperm in infected rats when compared with those of the control group. A significant reduction (P<0.01) in the levels of LH, FSH, testosterone and estradiol, associated with an increase in cortisol, was observed in serum of group B when compared with negative control. Additionally, NOx, lipid peroxidation and protein oxidation were enhanced in testicles, indicating the occurrence of cellular lesion. On histopathology, it was possible to observe testicular degeneration, among other disorders in infected animals. Therefore, based on these results, it is possible to conclude that the experimental infection with T. evansi caused changes in the levels of the main hormones of male rats associated with cellular injury.

Disruption of estrogen receptor signaling and similar pathways in the efferent ductules and initial segment of the epididymis

Seminiferous tubular atrophy may involve indirectly the disruption of estrogen receptor-α (ESR1) function in efferent ductules of the testis. ESR1 helps to maintain fluid resorption by the ductal epithelium and the inhibition or stimulation of this activity in rodent species will lead to fluid accumulation in the lumen. If not resolved, the abnormal buildup of fluid in the head of the epididymis and efferent ductules becomes a serious problem for the testis, as it leads to an increase in testis weight, tubular dilation and seminiferous epithelial degeneration, as well as testicular atrophy. The same sequence of pathogenesis occurs if the efferent ductule lumen becomes occluded. This review provides an introduction to the role of estrogen in the male reproductive tract but focuses on the various overlapping mechanisms that could induce efferent ductule dysfunction and fluid backpressure histopathology. Although efferent ductules are difficult to find, their inclusion in routine histological evaluations is recommended, as morphological images of these delicate tubules may be essential for understanding the mechanism of testicular injury, especially if dilations are observed in the rete testis and/or seminiferous tubules.

Signature Lesion:

The rete testis and efferent ductules can appear dilated, as if the lumens were greatly expanded with excess fluid or the accumulation of sperm. Because the efferent ductules resorb most of the fluid arriving from the rete testis lumen, one of two mechanisms is likely to be involved: a) reduced fluid uptake, which has been caused by the disruption in estrogen receptor signaling or associated pathways; or b) an increased rate of fluid resorption, which results in luminal occlusion. Both mechanisms can lead to a temporary increase in testicular weight, tubular dilation and atrophy of the seminiferous tubules.

Immunolocalization of estrogen and androgen receptors in the caput epididymidis of the fat sand rat (Psammomys obesus): Effects of seasonal variations, castration and efferent duct ligation

The fat sand rat (Psammomys obesus) is a model to study seasonal reproductive cycle changes and several metabolic disorders. In order to show a possible involvement of estrogens in the male reproductive functions, the expression of estrogen receptors (ESR1 and ESR2) and androgen receptor (AR) were investigated in the caput epididymidis of fat sand rats during the breeding season, resting season, after castration, after castration followed by testosterone treatment, and after ligation of efferent ducts. In the breeding season, principal cells presented a strong immunostaining of AR in both nuclei and cytoplasm, a strong staining of ESR1, mainly in the apical zone, and a strong immunoexpression of ESR2, mainly in nuclei. In the resting season, a moderate immunostaining of AR in both cytoplasm and nuclei was observed. ESR1 staining showed a strong immunoreactivity in the nuclei. In contrast, the nuclei were negative for ESR2. After castration, a low and selective signal distribution was observed: the nuclei were moderately positive for AR and ESR2, and negative for ESR1. After castration and testosterone treatment, an androgen-dependence for AR and the restoration of ESR1 but not ESR2 immunoexpression were observed. After ligation of the efferent ducts, a considerable reduction of AR immunoreactivity was observed in contrast to ESR1 and ESR2, which gave a strong immunostaining signal. These results illustrate the complexity of the regulation of the androgen and estrogen receptor expression in the epididymis and argue for the coexistence of both androgenic and estrogenic pathways.

Ductuli efferentes of the male Golden Syrian hamster reproductive tract

Efferent ductules are responsible for the transportation of spermatozoa from the testis to the epididymis and their epithelium is responsible for the reabsorption of over 90% of the luminal fluid. The purpose of this research was to characterize the gross morphology and histology of efferent ductules in the male Golden Syrian hamster. The efferent ductules emerge from rete testis with a unique polarity at the apex or cephalic pole of the testis. The number of efferent ductules varied from 3 to 10 with an average of 6.0 and blind ending ducts were observed in approximately 56% of the males. The ductules merged into a single common duct prior to entering the caput epididymidis. The proximal efferent ductule lumen was wider than the distal (conus and common ducts), consistent with reabsorption of most of the luminal fluid, as was morphology of the ductal epithelium. Non-ciliated cells in the proximal region had prominent endocytic apparatuses, showing both coated pits and apical tubules in the apical cytoplasm. Large basolateral, intercellular spaces were also present in the epithelium of the proximal region. Distal non-ciliated cells had an abundance of large endosomes and lysosomal granules. Localisation of sodium/hydrogen exchanger-3 (NHE3; SLC9A3) and aquaporins 1 and 9 (AQP1, AQP9) along the microvillus border was also consistent with ion transport and fluid reabsorption by this epithelium. In comparison, the caput epididymidis epithelium expressed only AQP9 immunostaining. Another unusual feature of the hamster efferent ductules was the presence of glycogen aggregates in the basal cytoplasm of small groups of epithelial cells, but only in the proximal ducts near the rete testis. Androgen (AR), estrogen (ESR1 and ESR2) and vitamin D receptors (VDR) were also abundant in epithelial nuclei of proximal and distal efferent ductules. In comparison, caput epididymidis showed very little immunostaining for ESR1.

Cadmium alters the reproductive endocrine disruption and enhancement of growth in the early and adult stages of Oreochromis mossambicus

Heavy metal cadmium (Cd) traces are able to promote growth (growth promoter) and induce early maturation in Oreochromis mossambicus fries of both sexes, whereas, in the adults, they degenerate the gonads and their function. The gathered data on length-weight relation, gonado-somatic index, hepato-somatic index, egg numbers and reproductive hormones such as gonadotropins (GtH-I and GtH-II) and gonadial hormones such as progesterone, testosterone and estradiol levels all prove Cd as an endocrine disruptor.

Immunoexpression of aromatase and estrogen receptors β in stem spermatogonia of bullfrogs indicates a role of estrogen in the seasonal spermatogonial mitotic activity

Bullfrog stem spermatogonia, also named primordial germ cells (PGCs), show strong testosterone immunolabeling in winter, but no or weak testosterone immunoexpression in summer. Thus, the role of testosterone in these cells needs to be clarified. In this study, we proposed to evaluate whether PGCs express aromatase and estrogen receptors, and verify a possible role of estrogen in PGCs seasonal proliferation. Testes of male adult bullfrogs, collected in winter (WG) and summer (SG), were fixed and embedded in historesin, for quantitative analysis, or paraffin for immunohistochemistry (IHC). The number of haematoxylin/eosin stained PGCs/lobular area was obtained. Proliferating cell nuclear antigen (PCNA), aromatase, estrogen receptor β (ERβ) and PCNA/ERβ double immunolabeling were detected by IHC. The number of PCNA-positive PGCs and the histological score (HSCORE) of aromatase and ERβ immunolabeled PGCs were obtained. Although the number of PGCs increased significantly in WG, a high number of PCNA-positive PGCs was observed in summer. Moreover, aromatase and ERβ HSCORE was higher in SG than WG. The results indicate that PGCs express a seasonal proliferative activity; the low mitotic activity in winter is related to the maximal limit of germ cells which can be supported in the large lobules. In SG, the increased ERβ and aromatase HSCORE suggests that testosterone is converted into estrogen from winter to summer. Moreover, the parallelism between the high PGCs mitotic activity and ERβ immunoexpression suggest a participation of estrogen in the control of the PGCs seasonal proliferative activity which guarantee the formation of new germ cysts from summer to next autumn.

The hormonal control of ejaculation

Hormones regulate all aspects of male reproduction, from sperm production to sexual drive. Although emerging evidence from animal models and small clinical studies in humans clearly point to a role for several hormones in controlling the ejaculatory process, the exact endocrine mechanisms are unclear. Evidence shows that oxytocin is actively involved in regulating orgasm and ejaculation via peripheral, central and spinal mechanisms. Associations between delayed and premature ejaculation with hypothyroidism and hyperthyroidism, respectively, have also been extensively documented. Some models suggest that glucocorticoids are involved in the regulation of the ejaculatory reflex, but corresponding data from human studies are scant. Oestrogens regulate epididymal motility, whereas testosterone can affect the central and peripheral aspects of the ejaculatory process. Overall, the data of the endocrine system in regulating the ejaculatory reflex suggest that widely available endocrine therapies might be effective in treating sexual disorders in these men. Indeed, substantial evidence has documented that treatments of thyroid diseases are able to improve some ejaculatory difficulties.

ATP-binding cassette transporter G2 activity in the bovine spermatozoa is modulated along the epididymal duct and at ejaculation

During their epididymal maturation, stabilizing factors such as cholesterol sulfate are associated with the sperm plasma membrane. Cholesterol is sulfated in epididymal spermatozoa by the enzyme estrogen sulfotransferase. Because of its role in the efflux of sulfate conjugates formed intracellularly by sulfotransferases, the ATP-binding cassette membrane transporter G2 (ABCG2) might have a role in the translocation of this compound across the plasma membrane. In the present study we showed that ABCG2 is present in the plasma membrane overlaying the acrosomal region of spermatozoa recovered from testis, epididymis, and after ejaculation. Although ABCG2 is also present in epididymosomes, the transporter is not transferred to spermatozoa via this mechanism. Furthermore, although epididymal sperm ABCG2 was shown to be functional, as determined by its ability to extrude Hoechst 33342 in the presence of the specific inhibitor Fumitremorgin C, ABCG2 present in ejaculated sperm was found to be nonfunctional. Additional experiments demonstrated that phosphorylation of ABCG2 tyrosyl residues, but not its localization in lipid rafts, is the mechanism responsible for its functionality. Dephosphorylation of ABCG2 in ejaculated spermatozoa is proposed to cause a partial protein relocalization to other intracellular compartments. Prostasomes are proposed to have a role in this process because incubation with this fraction of seminal plasma induces a decrease in the amount of ABCG2 in the associated sperm membrane fraction. These results demonstrate that ABCG2 plays a role in epididymal sperm maturation, but not after ejaculation. The loss of ABCG2 function after ejaculation is proposed to be regulated by prostasomes.

Post testicular sperm maturational changes in the bull: important role of the epididymosomes and prostasomes

After spermatogenesis, testicular spermatozoa are not able to fertilize an oocyte, they must undergo sequential maturational processes. Part of these essential processes occurs during the transit of the spermatozoa through the male reproductive tract. Since the sperm become silent in terms of translation and transcription at the testicular level, all the maturational changes that take place on them are dependent on the interaction of spermatozoa with epididymal and accessory gland fluids. During the last decades, reproductive biotechnologies applied to bovine species have advanced significantly. The knowledge of the bull reproductive physiology is really important for the improvement of these techniques and the development of new ones. This paper focuses on the importance of the sperm interaction with the male reproductive fluids to acquire the fertilizing ability, with special attention to the role of the membranous vesicles present in those fluids and the recent mechanisms of protein acquisition during sperm maturation.

Estrogen, efferent ductules, and the epididymis

Estrogen's presence in the male reproductive system has been known for over 60 years, but its potential function in the epididymis remains an important area of investigation. Estrogen is synthesized by germ cells, producing a relatively high concentration in rete testis fluid. There are two estrogen receptors (ESR), the presence of which in the head of the epididymis is well documented and consistent between species; however, in other regions of the epididymis, their expression appears to be isotype, species, and cell specific. ESR1 is expressed constitutively in the epididymis; however, its presence is downregulated by high doses of estrogen, making the design of experiments complicated, as the phenotype of the Cyp19a1(-/-) mouse does not resemble that of the Esr1(-/-) mouse. Ligand-independent and DNA-binding Esr1 mutant models further demonstrate the complexity and importance of both signaling pathways in maintenance of efferent ductules and epididymis. Data now reveal the presence of not only classical nuclear receptors, but also cytoplasmic ESR and rapid responding membrane receptors; however, their importance in the epididymis remains undetermined. ESR1 regulates ion transport and water reabsorption in the efferent ducts and epididymis, and its regulation of other associated genes is continually being uncovered. In the male, some genes, such as Aqp9 and Slc9a3, contain both androgen and estrogen response elements and are dually regulated by these hormones. While estrogen pathways are a necessity for fertility in the male, future studies are needed to understand the interplay between androgens and estrogens in epididymal tissues, particularly in cell types that contain both receptors and their cofactors.

Oestrogens and spermatogenesis

The role of oestrogens in male reproductive tract physiology has for a long time been a subject of debate. The testis produces significant amounts of oestrogenic hormones, via aromatase, and oestrogen receptors (ERs)alpha (ESR1) and ERbeta (ESR2) are selectively expressed in cells of the testis as well as the epididymal epithelium, depending upon species. This review summarizes the current knowledge concerning the presence and activity of aromatase and ERs in testis and sperm and the potential roles that oestrogens may have in mammalian spermatogenesis. Data show that physiology of the male gonad is in part under the control of a balance of androgens and oestrogens, with aromatase serving as a modulator.

Glucocorticoid receptor in the rat epididymis: expression, cellular distribution and regulation by steroid hormones

Glucocorticoids regulate several physiological functions, including reproduction, in mammals. Curiously, little is known about glucocorticoid-induced effects on the epididymis, an androgen-dependent tissue with vital role on sperm maturation. Here, RT-PCR, Western blot and immunohistochemical studies were performed to evaluate expression, cellular distribution and hormonal regulation of glucocorticoid receptor (GR) along rat epididymis. The rat orthologue of human GRalpha (mRNA and protein) was detected in caput, corpus and cauda epididymis and immunolocalized in the nucleus and cytoplasm of different epididymal cells (epithelial, smooth muscle and interstitial cells) and nerve fibers. Changes in plasma glucocorticoid and androgen levels differentially regulated GR expression in caput and cauda epididymis by homologous and heterologous mechanisms. In vivo treatment with dexamethasone significantly changed the expression of glucocorticoid-responsive genes and induced ligand-dependent GR nuclear translocation in epithelial cells from epididymis, indicating that GR is fully active in this tissue. Heterologous regulation of androgen receptor expression by glucocorticoids was also demonstrated in cauda epididymis. Our results demonstrate that the epididymis is under glucocorticoid regulation, opening new insights into the roles of this hormone in male fertility.

Estrogen receptors and function in the male reproductive system

A substantial advance in our understanding on the estrogen signaling occurred in the last decade. Estrogens interact with two receptors, ESR1 and ESR2, also known as ERα and ERβ, respectively. ESR1 and ESR2 belong to the nuclear receptor family of transcription factors. In addition to the well established transcriptional effects, estrogens can mediate rapid signaling, triggered within seconds or minutes. These rapid effects can be mediated by ESRs or the G protein-coupled estrogen receptor GPER, also known as GPR30. The effects of estrogen on cell proliferation, differentiation and apoptosis are often mediated by growth factors. The understanding of the cross-talk between androgen, estrogen and growth factors signaling pathways is therefore essential to understand the physiopathological mechanisms of estrogen action. In this review we focused on recent discoveries about the nature of the estrogen receptors, and on the signaling and function of estrogen in the male reproductive system.

Reproductive effects of di(2-ethylhexyl)phthalate in immature male rats and its relation to cholesterol, testosterone, and thyroxin levels

Phthalates are chemicals employed in several industrial products and there is a growing body of evidence demonstrating that they induce numerous adverse effects on the reproductive system. This study was carried out to assess possible alterations induced by the plasticizer di(2-ethylhexyl phthalate (DEHP) on cholesterol, testosterone, and thyroxine (total T4) levels, as well as to discuss the significance of these data in global changes observed in the reproductive tract of pubertal animals. Wistar rats aged 21 days received DEHP orally at 0, 250, 500, and 750 mg/kg/day for 30 days and were examined for different reproductive endpoints. At the end of the treatment, significant decreases in relative weight of testosterone-dependent organs, delayed preputial separation, and low serum testosterone were observed at the highest DEHP dose. The plot of the relationship between DEHP dose and serum cholesterol revealed a biphasic effect. The concentration of cholesterol in serum was significantly reduced at 250 mg/kg/day DEHP but returned to control values at 750 mg/kg/day. Cholesterol levels measured in testicular tissue increased with DEHP treatment. Serum T4 levels were not affected by DEHP at any dose, indicating the absence of a link between total thyroxin concentration and phthalate effects on cholesterol levels. Taken together these results indicate that effects observed in serum and testicular cholesterol levels may reflect distinct effects of DEHP on cholesterol synthesis and usage. These results confirm and extend previously reported findings showing that alterations in cholesterol balance may play a role in the suppression of steroidogenesis induced by DEHP in rats.

Regulation of epididymal contractility during semen emission, the first part of the ejaculatory process: a role for estrogen

INTRODUCTION

Ejaculation is an important step of the male sexual response, and consists of three separate phases: emission, ejection, and orgasm. In contrast to the erectile process, whose neurological and vascular mechanisms have been well elucidated, the pathophysiology of the ejaculatory process remains yet to be completely investigated. In humans, the emission and the ejection phases are regulated by an integrated and time-coordinated activity of the parasympathetic and sympathetic systems, which finally leads to sperm propulsion from the urethra. The first step in the ejaculatory process involves the epididymis, where a series of contractile waves begins, allowing sperm progression throughout the duct and toward the vas deferens. Interestingly, along with the complex neurological pathways, some non-neuronal factors (oxytocin [OT] and endothelin-1 [ET-1]) and sex hormones (estrogen) have been demonstrated to take part in the peripheral regulation of epididymal contractility.

AIM

This article reviews some of the physiological non-neuronal mechanisms underlying the epididymal contractility, and reports evidences of an estrogenic regulation.

METHODS

We reviewed here our and other groups' publications on the role of ET-1/OT and estrogens in modulating the epididymal contractility.

MAIN OUTCOME MEASURE

Data were obtained by an extensive examination of the published peer-reviewed literature on this topic.

RESULTS

Evidences support that, although the epididymis has a rich innervation, other local, non-neuronal factors participate in the nerve-independent epididymal contractility. ET-1 and OT, along with their cognate receptors, have been demonstrated to act, in an estrogen-dependent autocrine and paracrine loop, to regulate epididymal contractile activity in rabbit, and at least partially, in humans.

CONCLUSION

Ejaculation is the result of the complex, and today still not fully elucidated, interplay between neuronal and non-neuronal, sex-steroid-dependent factors.

Epididymis expresses the highest 5'-deiodinase activity in the male reproductive system: kinetic characterization, distribution, and hormonal regulation

We characterized the enzymes that catalyze the deiodination of T(4) to T(3) in the male reproductive tract. Testis, epididymis (EPI), seminal vesicles, prostate, bulbourethral glands, spermatozoa, and semen were taken from sexually mature rats (300 g). Iodothyronine 5'-deiodinase (5'-D) activity was quantified by the radiolabeled-iodide-release method. 5'-D activity was 10-fold higher in EPI and semen than in the rest of the tissues. In EPI, semen, and prostate, the enzymatic activity was completely inhibited by 1 mm 6-n-propyl-2-thiouracil, whereas in the other tissues the inhibition was partial (50%). The high susceptibility to 6-n-propyl-2-thiouracil inhibition, a ping-pong kinetic pattern, and low cofactor (Michaelis Menten constant for dithiothreitol=0.7 mm) and high substrate (Michaelis Menten constant for reverse T(3)=0.4 microm) requirements indicate that EPI 5'-D corresponds to type 1 deiodinase (D1). Real-time RT-PCR amplification of D1 mRNA in this tissue confirms this conclusion. The highest EPI D1 expression occurred at the onset of puberty and sexual maturity, and in the adult, this activity was more abundant in corpus and caput than in the caudal region. EPI D1 expression was elevated under conditions of hyperthyroidism and with addition of 17beta-estradiol. Our data also showed a direct association between D1 and a functional epididymis marker, the neutral alpha-glucosidase enzyme, suggesting that local generation of T(3) could be associated with the development and function of EPI and/or spermatozoa maturation. Further studies are necessary to analyze the possible physiological relevance of 5'-D in the male reproductive system.

Effects of the antiestrogen fulvestrant (ICI 182,780) on gene expression of the rat efferent ductules

The efferent ductules express the highest amount of estrogen receptors ESR1 (ERalpha) and ESR2 (ERbeta) within the male reproductive tract. Treatment of rats with the antiestrogen fulvestrant (ICI 182,780) causes inhibition of fluid reabsorption in the efferent ductules, leading to seminiferous tubule atrophy and infertility. To provide a more comprehensive knowledge about the molecular targets for estrogen in the rat efferent ductules, we investigated the effects of ICI 182,780 treatment on gene expression using a microarray approach. Treatment with ICI 182,780 increased or reduced at least 2-fold the expression of 263 and 98 genes, respectively. Not surprisingly, several genes that encode ion channels and macromolecule transporters were affected. Interestingly, treatment with ICI 182,780 markedly altered the expression of genes related to extracellular matrix organization. Matrix metalloproteinase 7 (Mmp7), osteopontin (Spp1), and neuronal pentraxin 1 (Nptx1) were among the most altered genes in this category. Upregulation of Mmp7 and Spp1 and downregulation of Nptx1 were validated by Northern blot. Increase in Mmp7 expression was further confirmed by immunohistochemistry and probably accounted for the decrease in collagen content observed in the efferent ductules of ICI 182,780-treated animals. Downregulation of Nptx1 probably contributed to the extracellular matrix changes and decreased amyloid deposition in the efferent ductules of ICI 182,780-treated animals. Identification of new molecular targets for estrogen action may help elucidate the regulatory role of this hormone in the male reproductive tract.

Expression of aquaporins in the efferent ductules, sperm counts, and sperm motility in estrogen receptor-alpha deficient mice fed lab chow versus casein

Estrogens play an important role in the male reproductive tract, and this is especially so for the efferent ductules, where alpha-estrogen receptors (ERalpha) have been localized. Mice deficient in ERalpha (alphaERKO mice) are infertile, and the effect appears to be due in part to retention of water at the level of the efferent ductules. In the present study, we examined the consequences of ERalpha deletion on the distribution of certain aquaporins (AQPs), water protein channels, in the efferent ductules and on sperm numbers and motility. In addition, the effects of feeding mice a regular lab chow diet, which contains phytoestrogens, known to affect male reproductive tract functions, and a casein diet, which lacks phytoestrogens, were also assessed. Light microscope immunolocalizations of AQP-1 and AQP-9 revealed dramatic reduction and patchier staining in alphaERKO mice with distal areas of the efferent ductules being more affected than proximal areas. No other changes in immunolocalizations were noted as a consequence of diet. Computer-assisted sperm analyses demonstrated a 62% reduction in cauda epididymal sperm/ml in alphaERKO mice fed lab chow, whereas 87% fewer sperm/ml were observed in alphaERKO mice fed casein, suggesting an enhanced role for sperm production and concentration in a diet containing phytoestrogens. All sperm motility parameters were altered to some degree in alphaERKO mice fed lab chow. Alterations in sperm motility parameters were also detected, but were less dramatic in alphaERKO mice fed casein. These data suggest that the decrease in AQP expression in the efferent ductules of alphaERKO mice contributes in part to water retention in this tissue, eventually leading to backflow of water into the testis, with subsequent decreases in sperm concentration and motility. The data also suggest that phytoestrogens, which are present in regular lab chow, can influence the male reproductive tract with and without the presence of ERalpha, promoting efferent ductule and epididymal functions when ERalpha is expressed, but inhibiting these same functions when ERalpha is missing. Taken together the data underscore the importance of estrogens and ERalpha in maintaining sperm maturation and preventing male infertility.

Expression of functional aromatase in the epididymis: role of androgens and LH in modulation of expression and activity

The primary source of 17beta-estradiol (E2) in the male is the testis, which expresses the enzyme complex aromatase that is involved in E2 biosynthesis. However, recent evidences suggest that the epididymis is also capable of E2 biosynthesis. Our results demonstrate the presence of cytochrome P450 aromatase (P450(AROM)) and 17beta-hydroxysteroid dehydrogenase I messenger ribonucleic acid (mRNA) in the caput and cauda regions of rat epididymis. The androgenic substrates testosterone and androstenedione could be utilized by the rat epididymal aromatase for E2 biosynthesis as assessed by radioimmunoassay. P450(AROM) expression is transcriptionally regulated in a tissue-specific manner by various factors including androgens and luteinizing hormone (LH). Androgens could positively modulate epididymal P450(AROM) mRNA levels as assessed by castration studies, treatment with flutamide or in vitro incubation of tissue minces with 5 alpha-dihydrotestosterone (DHT). Several extra-gonadal tissues including the epididymis are known to express LH receptors (LHR). Our study revealed a higher level of LHR mRNA expression in the cauda region compared to the caput. Caudal membrane extracts could bind human chorionic gonadotropin (hCG), which resulted in the production of cAMP. Interestingly, hCG could also regulate P450(AROM) mRNA expression in vitro and enhance E2 biosynthesis. Together our results highlight the presence of a functional aromatase in the epididymis that is subject to regulation by LH and androgens.

Infant feeding with soy formula milk: effects on puberty progression, reproductive function and testicular cell numbers in marmoset monkeys in adulthood

BACKGROUND

This marmoset study addresses concerns about feeding human male infants with soy formula milk (SFM).

METHODS

From age 4 to 5 days, seven male co-twin sets were fed standard formula milk (SMA) or SFM for 5-6 weeks; blood samples were subsequently collected at 10-week intervals. Testes from co-twins killed at 120-138 weeks were fixed for cell counts.

RESULTS

SFM- and SMA-fed twins showed normal weight gain; puberty started and progressed normally, based on blood testosterone measurements. Body weight, organ weights (prostate, seminal vesicles, pituitary, thymus and spleen) and penis length were comparable in co-twins. All SMA- and 6/7 SFM-fed males were fertile. Unexpectedly, testis weight (P = 0.041), Sertoli (P = 0.025) and Leydig cell (P = 0.026) numbers per testis were consistently increased in SFM-fed co-twins; the increase in Leydig cell numbers was most marked in males with consistently low-normal testosterone levels. Seminiferous epithelium volume per tubule showed a less consistent, non-significant increase in SFM-fed males; raised germ cell numbers per testis, probably due to increased Sertoli cells, conceivably resulted in larger testes. Average lumen size, although greater in SFM-fed group, was inconsistent between co-twins and the difference was not significant.

CONCLUSIONS

Infant feeding with SFM has no gross adverse reproductive effects in male marmosets, though it alters testis size and cell composition, and there is consistent, if indirect, evidence for possible 'compensated Leydig cell failure'. Similar and perhaps larger changes likely occur in adult men who were fed SFM as infants.

Spermatogenesis and sperm transit through the epididymis in mammals with emphasis on pigs

Starting from the period of testis differentiation, the Sertoli cell plays a pivotal role in the development of a functional testis. FSH is the major mitotic factor for Sertoli cells. Because the supporting capacity of Sertoli cells is relatively fixed for each species, their total number per testis, established just before puberty (approximately 4 months in pigs), dictates the potential for sperm production. In contrast to Sertoli cells that are still undifferentiated, mature Leydig cells are already present at birth in pigs. Spermatogenesis lasts from 30 to 75 days in mammals, and this time period is under the control of the germ cell genotype. In boars, each spermatogenic cycle and the entire spermatogenic process lasts 8.6-9.0 and approximately 40 days, respectively. The sperm transit through the epididymis takes approximately 10 days in pigs and this is within the range cited for most mammals. Germ cell loss occurs normally during spermatogenesis, mainly during the spermatogonial and meiotic phases. In pigs, significant germ cell loss also takes place during spermiogenesis. In mammals in general, including pigs, only 2-3 out of a possible 10 spermatozoa are produced from each differentiated type A1 spermatogonium. The high supporting capacity of Sertoli cells and the short duration of the spermatogenic cycle are the main factors responsible for the comparatively high spermatogenic efficiency of pigs.

Male Reproductive Toxicity of Trichloroethylene: Sperm Protein Oxidation and Decreased Fertilizing Ability1

The objective of the present study was to characterize and investigate potential mechanisms for the male reproductive toxicity of trichloroethylene (TCE). Male rats exposed to TCE in drinking water exhibited a dose-dependent decrease in the ability to fertilize oocytes from untreated females. This reduction in fertilizing ability occurred in the absence of treatment-related changes in combined testes/epididymides weight, sperm concentration, or sperm motility. In addition, flow cytometric analysis showed that there were no treatment-related differences in sperm mitochondrial membrane potential or acrosomal stability. TCE caused slight histological changes in efferent ductule epithelium, coinciding with the previously reported ductule localization of cytochrome P450 2E1. However, no alterations were noted in the testis or in any segment of the epididymis. Because there were no treatment-related changes to sperm indices and no clear pathological lesions to explain the reduced fertilization, the present study investigated TCE-mediated sperm oxidative damage. Oxidized proteins were detected by immunochemical techniques following the derivatization of sperm protein carbonyls with dinitrophenyl hydrazine. Immunochemical staining of whole, intact sperm showed the presence of halos of oxidized proteins around the head and midpiece of sperm from TCE-treated animals. The presence of oxidized sperm proteins was confirmed by Western blotting using in vitro-oxidized sperm as a positive control. Thiobarbituric acid reactive substances analyses showed a dose-dependent increase in the level of lipid peroxidation in sperm from treated animals, as well. Oxidative damage to sperm may explain the diminished fertilizing capacity of exposed animals and provide another mechanism by which TCE can adversely affect reproductive capabilities in the male.

Neonatal coadministration of testosterone with diethylstilbestrol prevents diethylstilbestrol induction of most reproductive tract abnormalities in male rats

The primary purpose of this study was to evaluate whether the coadministration of testosterone (TE; 200 micro g) with 10 micro g of diethylstilbestrol (DES) between days 2 and 12 postnatally could prevent the adverse gross reproductive tract changes and associated loss of androgen receptor (AR) expression induced by DES treatment alone. Various endpoints (rete testis area, efferent duct lumen area, epithelial cell height of efferent ducts, and vas deferens) were quantified to check for the abnormal changes that have been shown to occur after neonatal treatment with a high dose (10 micro g) of DES. Additionally, DES induction of an aberrant pattern of estrogen receptor alpha (ER-alpha) immunoexpression in the vas deferens and seminal vesicles was evaluated. The coadministration of DES with TE prevented the induction of all but one of the abnormalities induced by DES treatment on its own, coincident with the restoration of normal/supranormal TE levels and normal immunoexpression of the AR and ER-alpha in the tissues studied. The exception was DES-induced lumenal distension of the efferent ducts, which was only partially prevented by the coadministration of DES with TE. These evaluations were made on day 18, but the described abnormalities were already somewhat evident by day 8 in DES-treated animals. It was therefore tested whether a delay of TE replacement until days 8-12 was still able to reverse the abnormalities already induced by DES treatment alone. A delayed treatment with TE reversed the adverse changes in epithelial cell height and in ER-alpha and AR immunoexpression in the same tissues by day 18; however, rete testis overgrowth was only partially prevented, and efferent duct distension was not prevented at all. These results provide further evidence that DES-induced disorders of reproductive tract development in the male result from a disturbance of the androgen-estrogen balance rather than from estrogen action alone.

Nongenomic estrogen action regulates tyrosine phosphatase activity and tuberin stability

Estrogen action and tuberin function has been suggested to play a crucial role in the proliferation of lung smooth muscle-like cells and/or myofibroblasts in pulmonary lymphangioleiomyomatosis (LAM). Tuberin is a tumor suppressor phosphoprotein, which also regulates fluid phase endocytosis. Its activity, turnover and complex association with hamartin depends on its phosphorylation status. We have recently reported that nongenomic estrogen action regulates the phosphorylation status of several cytoplasmic proteins. Herein, we demonstrate that estrogen increases tyrosine phosphatase activity, which can be abrogated by antiestrogen ICI 182780 and tyrosine phosphatase inhibitor bpV(phen), but not by the protein synthesis inhibitor cyclohexamide. Furthermore, we show that estrogen transiently enhances the turnover of tuberin, which follows an inverse pattern to that observed for tyrosine phosphatase and endocytosis activity. We showed that tuberin phosphorylation protects it from degradation and induces its accumulation in female human lung fibroblasts and myofibroblasts. Our results suggest that nongenomic estrogen action induces tyrosine phosphatase activity that regulates stability of tyrosine phosphorylated proteins, including tuberin, which may play a crucial role in cellular specific functions such as endocytosis.

Effect of hCG injection on prostaglandin E concentrations in ram seminal plasma

Ram and bull seminal plasma, respectively, contain 0.5-20 microg PGE/ml and 5-10 ng PGE/ml. To demonstrate that PGE concentrations in the seminal plasma are related to sperm quality and could be affected by hormonal stimulation in vivo, four rams were injected with 500 IU hCG, in and out of season. The rams responded 1 week after hCG with a 1.5- to 4-fold increase in seminal plasma PGE. The PGE peak was temporally separate from the hCG-induced rise in seminal plasma testosterone which was observed after 1 day. Using a simulated cryptochid ram, peaks in seminal fluid PGE were found to be associated with increased sperm velocity and sperm counts. In bulls, PGE concentrations in the seminal plasma of good bulls were significantly higher than that found in poor and cryptorchid bulls.

Induction of reproductive tract developmental abnormalities in the male rat by lowering androgen production or action in combination with a low dose of diethylstilbestrol: evidence for importance of the androgen-estrogen balance

This study tested the hypothesis that testis/reproductive tract abnormalities induced in the rat by neonatal treatment with diethylstilbestrol (DES) result from disturbance of the androgen-estrogen balance. Male rats were treated neonatally with a dose of DES (0.1 micro g) that induced either no or small effects on its own or with a dose (10 micro g) that induced major reproductive tract abnormalities. To allow quantification, the abnormalities chosen for study were distension of the rete testis and efferent ducts and reduction in epithelial cell height in the efferent ducts and vas deferens. To alter the androgen-estrogen balance, other rats were treated with DES (0.1 micro g) in combination with a treatment to suppress either androgen production [GnRH antagonist (GnRHa)] or androgen action (flutamide); other rats were treated with GnRHa or flutamide alone. Testosterone levels were measured to verify the effects of treatment. Combined administration of DES (0.1 micro g) plus GnRHa or flutamide induced significantly greater distension/overgrowth of the rete testis and efferent ducts (ED) and a reduction in epithelial cell height of the ED than did DES (0.1 micro g) administered alone. Neither GnRHa nor flutamide affected rete or ED distension when administered alone, but both significantly reduced ED epithelial cell height. Neonatal treatment with bisphenol-A (100 micro g) with or without GnRHa had no significant effect on any of these parameters. In contrast to the ED, a reduction in cell height of the vas deferens was induced to an equal extent by DES (10 micro g), DES (0.1 micro g) with GnRHa, and GnRHa alone, suggesting greater sensitivity of this tissue to both androgen and estrogen action. The induction of major abnormalities in rats treated with DES (10 micro g) was coincident with loss of androgen receptor immunoexpression in affected tissues. Reduced androgen receptor immunoexpression was also induced by combined treatment with DES (0.1 micro g) plus GnRHa or flutamide, whereas treatment with any of these compounds alone had no or only minor effects. These findings suggest that reduced androgen action sensitizes the reproductive tract to estrogens, demonstrating that the balance in action between androgens and estrogens, rather than their absolute levels, may be of fundamental importance in determining normal or abnormal development of some regions of the male reproductive tract.