Stage-dependent changes in spermatogenesis and Sertoli cells in relation to the onset of spermatogenic failure following withdrawal of testosterone

Exposure of young rats to high estrogen doses leads to degeneration of elongated spermatids

Single high doses of estrogen (35 mg/kg body weight) were administered to young rats aiming to exacerbate its effects on germ cell populations. The short-term (1 week) and medium-term (7 weeks) consequences of this estrogenic treatment (ET) on the testis were evaluated using light and electron microscopies, quantitative methods and TUNEL reaction. Short-term ET led to 50% atrophy of the testis, however, in the medium term the gonado-somatic index was recovered. No histopathological alterations were found at seminiferous epithelium except for short-term severe degeneration of elongated spermatids (EL) and low frequency of these cells in both time intervals. Two morphologically distinct patterns of degeneration were observed: (1) clusters of EL which were TUNEL-negative and exhibited bizarre appearance and nuclear fragmentation, (2) isolated apoptotic EL within the cytoplasm of Sertoli cells (SC). Both degenerative phenomena were more frequent in stages III-VIII of seminiferous cycle, whereas at stages I and II only coiling of flagellum was observed. One week after ET, small amounts of EL were detected in stages IX-XII, suggesting spermiation failure. Signs of functional SC damage such as an accumulation of myelin-like inclusions in their cytoplasm were observed in the short but not medium-term. However, the apoptotic rates still remained five times higher and the number of elongated spermatids was three-fold lower. Our data indicate that exposure to a high dose of estrogen around puberty has stage-specific effects on the testis and causes massive degeneration of elongated spermatids.

Morphometric and ultrastructural analysis of stage-specific effects of Sertoli and spermatogenic cells seen after short-term testosterone treatment in young adult rat testes

The effects of testosterone treatment on spermatogenesis in the rat have been investigated by morphometric and structural analysis at the ultrastructural level in stages VII-IX. The aim has been to characterize the changes in Sertoli and spermatogenic cells to elucidate the mechanism of testosterone effects on spermatogenesis and to test the possibilities of developing male contraceptives. In stage VII, the morphometric parameters of volume and surface area in Sertoli cells (see abbreviations below): and the morphometric parameter of volume in the spermatogenic cells such as V(VPG,T), V(VPC,T), V(VrPT,T) and V(VelPT,T) decreased. In stage VIII, the respective values of Sertoli cells, VSN, and VSN/VSC decreased while SSJ increased, and the respective morphometric parameters in the spermatogenic cells, V(VPG,T), V(VPC,T), and V(VrPT,T) increased. In stage IX, in Sertoli cells VSC, VSN, VSN/VSC, and SSJ remained unchanged. In spermatogenic cells V(VPG,T), V(VPC,T), and V(VrPT,T) increased. Further, in all stages, a close apposition of mitochondria and rough endoplasmic reticulum in basolateral cytoplasm of Sertoli cells suggested active protein synthesis. In elongated spermatids in stage IX the microtubular manchette became disorganized. This disorganization and the unexpected shift after testosterone treatment from decrease in several morphometric parameters in stage VIII to increases in stage IX cannot be explained by alterations in testosterone (T), LH, FSH, and their respective receptors. Therefore, still unknown regulatory factors in spermatogenesis are apparently involved in the developmental interactions between Sertoli and spermatogenic cells.

Effects of altered epididymal sperm transit time on sperm quality

The epididymal sperm transit time seems to have an important role in the process of sperm maturation, and it seems that alterations to the transit can harm the process. The aim of the present work was to evaluate the influence of altered sperm transit time through the epididymis on sperm parameters and fertility of rats, as well as the role of testosterone in the alterations. Sprague-Dawley adult male rats were randomly assigned to four different groups and were treated for 12 days: (i) 10 microg/rat/day DES, to accelerate the transit; (ii) 6.25 mg/kg/day guanethidine sulphate, to delay the transit; (iii) same treatment as group 1, plus androgen supplementation; (iv) control animals received the vehicles. Guanethidine treatment delayed the sperm transit time through the epididymal cauda, provoking increased sperm reserves in this region. Animals exposed to DES showed an acceleration of sperm transit time in the epididymis, and consequently decreased sperm density in both epididymal regions, the caput-corpus and cauda, and diminished sperm motility. In both cases sperm production was not altered. Testosterone supplementation was able to restore the transit time to values close to normality, as they were higher than in the control rats. The same occurred in relation to sperm motility. Rats exposed to DES presented lower fertility after in utero artificial insemination using sperm collected from the proximal cauda epididymis. Therefore, it was concluded that the acceleration of rat sperm transit time appeared to harm normal sperm maturation, thus decreasing sperm quality and fertility capacity, in an androgen-dependent way.

Testosterone upregulation of tissue type plasminogen activator expression in Sertoli cells : tPA expression in Sertoli cells

Our previous studies have demonstrated that tissue type plasminogen activator (tPA) might be involved in matrix degradation of blood-testis barrier in rat. In this study, we have further investigated the effect of testosterone (T) on tPA production in rat Sertoli cells. Our results showed that Sertoli cells isolated from rat testes at various ages in vitro secreted tPA in an age-dependent manner. The tPA activity was detected on day 20 after birth, and reached maximum on day 60. The Sertoli cells isolated from the testes on day 20 were then cultured in the presence or absence of testosterone, FSH, and forskolin, the tPA activities were upregulated by T, FSH and forskolin. Addition of H89 or U0126, both inhibited the testosterone-, FSH-, and forskolin-induced tPA expression. It is suggested that FSH- and testosterone-stimulated tPA expression in Sertoli cells may be via PKA and ERK signal transduction. Furthermore, we have observed that testosterone stimulated tPA secretion at all the stages of spermatogenesis (II-VI, VII-VIII, IX-XII and XIII-I), the highest stimulation of tPA activity was observed at stages VII-VIII. This study further suggests that testosterone-induced tPA activity in the Sertoli cells might be related to the function of blood-testis barrier opening and/or closing.

Sterilization of male stray dogs with a single intratesticular injection of calcium chloride: a dose-dependent study

OBJECTIVE

To study a method of chemical sterilization and its efficacy in adult male stray dogs.

METHODS

Sterilization was performed 45 days after a single bilateral intratesticular injection of calcium chloride (CaCl(2)) at the doses of 5, 10, 15 or 20 mg per testis per kg body weight.

RESULTS

Histomorphological measures of testes showed total necrosis of testicular tissue at 45 days after an injection of either 10 or 15 or 20 mg CaCl(2) along with fibrosis and hyalinization in seminiferous tubules and interstitial spaces. Infiltration of leucocytes was also observed with the 10- or 15-mg dose. Disintegration of germ cell arrangement in seminiferous tubules and washing out of germ cells from the tubules were noted with the 5-mg dose. Relative organ weight, epididymal sperm count, plasma and intratesticular concentrations of testosterone, testicular activities of Delta(5),3beta-hydroxysteroid dehydrogenase (Delta(5),3beta-HSD), 17beta-hydroxysteroid dehydrogenase (17beta-HSD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) and testicular contents of glutathione (GSH) and glutathione disulphide (GSSG) and the ratio of GSH/GSSG, all were declined in each of the calcium chloride treated groups in comparison to the control group. Increases occurred in testicular malondialdehyde (MDA) and plasma concentrations of LH and FSH with each of the treatments by comparison with the control group. Plasma concentrations of cortisol, fasting blood sugar level, blood urea nitrogen as well as packed cell volume (PCV) and total plasma protein were recorded to monitor the changes in chronic stress in the experimental animals. Changes in these parameters were not significant.

CONCLUSION

An intratesticular injection of CaCl(2) at specified doses could be a suitable method of sterilization in preference to surgical castration of dogs.

Evaluation on the phagocytosis of apoptotic spermatogenic cells by Sertoli cells in vitro through detecting lipid droplet formation by Oil Red O staining

During spermatogenesis, more than half of the differentiating spermatogenic cells undergo apoptosis before they mature into spermatozoa. Ultrastructure studies showed that the formation of lipid droplets in Sertoli cells was associated with phagocytosis of residual bodies and apoptotic germ cells by Sertoli cells. Here, a relationship between the phagocytosis of apoptotic spermatogenic cells and lipid droplet formation in Sertoli cells was studiedin vitroby Oil Red O (ORO) staining. The results confirmed that the formation of lipid droplets was a result of phagocytosis of apoptotic spermatogenic cells in Sertoli cells. By comparing phagocytosis of apoptotic spermatogenic cells and thymocytes by Sertoli cells to that by macrophages, we demonstrated that the lipid droplets accumulation in phagocytes depended on phagocytosed apoptotic cell type, but not phagocyte type. However, the size of lipid droplets was related to the type of phagocytes. By this approach, we found that Sertoli cells at different postnatal stages of development had a similar phagocytic ability. These results suggested that the detection of lipid droplets by ORO staining was a practical method to evaluate the phagocytic functions of Sertoli cellsin vitro. This approach could also be considered as anin vitromodel to study the lipid formation, metabolism, and function in Sertoli cells.

Dacarbazine induces genotoxic and cytotoxic germ cell damage with concomitant decrease in testosterone and increase in lactate dehydrogenase concentration in the testis

Treatment of cancers with cytotoxic agents such as alkylating drugs often, but not always results in transient to permanent testicular dysfunction. The present study was planned to investigate the effects of dacarbazine [5-(3,3-dimethyltriazeno) imidazole-4-carboxamide] on testicular function in mice. Swiss albino mice (9-12 weeks old) were treated with 0, 5, 25, 50, or 100mg/kg body weight/day dacarbazine (i.p.) for 5 days at intervals of 24h between treatments. Mice were sacrificed on days 7, 14, 21, 28, 35, 49, and 70 after the last treatment (6 mice/dose/sample time), and the epididymal sperm count, sperm motility, sperm morphology, testicular histopathology (qualitative histopathology, seminiferous tubular diameter and epithelial height), and intra-testicular levels of testosterone and lactate dehydrogenase were assessed. Dacarbazine decreased the body weight only on day 28 at 25mg/kg dose-level, but increased the paired testes weights at 50mg/kg on day 7, at 25-100mg/kg on day 14, and at 25 and 50mg/kg on day 21 (P<0.05-0.01; one-way ANOVA and Bonferroni's post hoc test). The sperm count was decreased on all sampling days except at 5 and 25mg/kg dose-levels on day 70, but with severe oligospermia on days 28 and 35 (P<0.05-0.001). The sperm motility was decreased at 100mg/kg on days 14 and 21, at 5, 25, and 100mg/kg on day 28, and at all dose-levels on day 35 (P<0.05-0.001). Dacarbazine induced both head and tail abnormalities and some sperms with cytoplasmic droplets, but significant increase was seen in all dose groups on days 14 and 21, and at 100mg/kg dose-level on day 35. Drug-induced epithelial sloughing was seen on days 14-35 and other histopathological changes observed were vacuoles and abnormal cells. The STD was increased at 25-100mg/kg on day 7, at all dose-levels on day 14, at 50-100mg/kg on days 21 and 28, but without any effects on days 35-70 (P<0.05-0.001), and the tubular lumen was found dilated. The SE was increased on days 7, 21 and 28 at 100mg/kg and on day 14 at 50-100mg/kg. Dacarbazine reduced the intra-testicular testosterone level at 100mg/kg on day 7, at 5, 50 and 100mg/kg on day 14, at all dose-levels on days 21, 28, and 35, and at 50mg/kg on day 49 (P<0.05-0.001). The intra-testicular lactate dehydrogenase concentration increased at all dose-levels up to day 35, but without any effect on days 49 and 70 (P<0.05-0.001). There was no particular dose-response of dacarbazine on any parameters tested. The sperm count (except on day 7-positive correlation; Pearson product moment correlation) or sperm motility did not have any relation but increase in abnormal sperms showed negative correlation with decrease in testosterone level on days 7, 21 and 28. Decrease in sperm count was in negative correlation on days 14 and 35, and increase in abnormal sperms showed positive correlation on day 35 with increase in LDH level. Finally, the decrease in sperm motility had no correlation with increase in abnormal sperm shapes. We conclude that dacarbazine is genotoxic and cytotoxic to the mouse testis in a transient fashion, and these effects are exerted along with decrease in testosterone and increase in lactate dehydrogenase levels in the testis.

Histological changes of the testis and epididymis in adult rats as a result of Ley dig cell destruction after ethane dimethane sulfonate treatment: a morphometric study

AIM

To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion.

METHODS

Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate (EDS, 75 mg/kg) and the same number of animals were injected with normal saline as a control. At days 7 and 12 (after treatment), respectively, half of the animals from each group were killed. The testes and epididymides were removed and tissue blocks embedded in methacrylate resin. The cell number per testis was estimated using the stereological optical disector and some other parameters were obtained using other morphometric methods.

RESULTS

The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis. At day 7 after EDS treatment, many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts. At day 12, a looser arrangement of spermatids and spermatocytes became evident, with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen; the numbers (per testis) of non-type B spermatogonia and spermatocytes were similar to controls, whereas that of type B spermatogonia increased by 59%, and that of early round, elongating and late elongated spermatids decreased by 37%, 72% and 52%, respectively.

CONCLUSION

The primary spermatogenic lesions following EDS administration were (i) spermiation failure and (ii) detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.

FSH and testosterone signaling in Sertoli cells

Testosterone and follicle-stimulating hormone (FSH) are required to obtain full reproductive potential. In the testis, somatic Sertoli cells transduce signals from testosterone and FSH into the production of factors that are required by germ cells as they mature into spermatozoa. Recent advances in identifying new signaling pathways that are regulated by FSH and testosterone have allowed for refinement in the understanding of the independent, overlapping and synergistic actions of these hormones. In this review, we discuss the signaling pathways that are regulated by FSH and testosterone as well as the resulting metabolic and gene expression changes that occur as related to Sertoli cell proliferation, differentiation and the support of spermatogenesis.

Androgen Regulation of Stage-Dependent Cyclin D2 Expression in Sertoli Cells Suggests a Role in Modulating Androgen Action on Spermatogenesis1

Regulation of spermatogenesis involves stage-dependent androgen action on Sertoli cells, but the pathways involved are unclear. We assessed if cyclin D2 could play a role. In rats, Sertoli cell nuclear, stage-dependent immunoexpression of cyclin D2 switched on after Day 10 and persisted through Day 35, but disappeared by adulthood. However, ethane dimethane sulfonate (EDS)-induced testosterone withdrawal in adult rats for 6 days induced stage-dependent cyclin D2 immunoexpression in Sertoli cells, with highest expression at stages IX-XII and nondetectable at stages VI-VIII (opposite that for androgen receptor [AR] immunoexpression). In EDS-treated rats, a single injection of testosterone but not of estrogen reversed this change in 4 h, and testosterone administration from the time of EDS treatment prevented expression of cyclin D2 in Sertoli cells. The EDS-induced changes in cyclin D2 immunoexpression were matched by changes in expression of Ccnd2 (cyclin D2) mRNA in isolated stage-dissected tubules. Treatment of adult rats with flutamide induced stage-dependent cyclin D2 immunoexpression in Sertoli cells within 18 h, and confocal microscopy revealed that immunoexpression of AR and cyclin D2 were mutually exclusive within individual seminiferous tubules in these animals. Sertoli cell-selective ablation of the AR in mice using Cre/loxP technology also resulted in stage-dependent Sertoli cell cyclin D2 immunoexpression. Downstream from cyclin D2 action is retinoblastoma 1 (RB1), a tumor suppressor protein, immunoexpression of which paralleled stage-dependent AR expression in Sertoli cells; RB1 stage specificity disappeared after EDS treatment. These results point to a non-cell cycle role for cyclin D2 and RB1 in mature Sertoli cells in the stage-dependent mechanisms regulated by AR expression and androgen action.

Evaluation of single intratesticular injection of calcium chloride for nonsurgical sterilization of male Black Bengal goats (Capra hircus): a dose-dependent study

This study describes the induction of chemosterilization in three groups each of six adult male Black Bengal goats at 30 days after a single bilateral intratesticular injection of a calcium chloride (CaCl(2), 2H(2)O) solution at the doses of 10, 20 or 40 mg/kg body weight/testis, always in a 2 ml volume of normal saline. Another one group of animals received only 2 ml of normal saline per testis as a control. The induction of chemosterilization was measured using relative testicular weight as well as histomorphological parameters including seminiferous tubular architecture and germ cell association in seminiferous tubules along with morphology of the interstitial space. Biochemical markers included activities of testicular Delta(5), 3beta-hydroxysteroid dehydrogenase (Delta(5), 3beta-HSD), 17beta-hydroxysteroid dehydrogenase (17beta-HSD), catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) as well as monitoring the level of testicular thiobarbituric acid reactive substances (TBARS), conjugated dienes and reduced glutathione (GSH) content along with plasma concentrations of testosterone, LH and FSH. Histomorphological measures of testes showed total necrosis of testicular tissue at 30 days after an injection of either 20 or 40 mg CaCl(2) along with fibrosis in seminiferous tubules and interstitial spaces. Infiltration of leucocytes was observed with the 40 mg dose. Disintegration of germ cell arrangement in seminiferous tubules and washing out of germ cells from the tubules were noted with the 10mg dose. Relative organ weights, plasma concentrations of testosterone, testicular activities of Delta(5), 3beta-HSD, 17beta-HSD, catalase, GPx, GST, and SOD and testicular contents of GSH all were declined. Increases occurred in testicular TBARS, conjugated dienes and plasma concentrations of LH and FSH with each of the treatments by comparison with the control group. Plasma concentrations of cortisol and fasting blood sugar level as well as packed cell volume (PCV) and total plasma protein were recorded to monitor the changes of chronic stress in the experimental animals. Changes in these parameters were not significant. An intratesticular injection of calcium chloride at specified doses could be a suitable method of sterilization in preference to surgical castration of goats.

Hormonal regulation of spermatogenesis

Proper functioning of the mammalian testis is dependent upon an array of hormonal messengers acting through endocrine, paracrine, and autocrine pathways. Within the testis, the primary messengers are the gonadotrophins, follicle stimulating hormone and luteinizing hormone, and the androgens. Abundant evidence indicates that the role of the gonadotrophins is to maintain proper functioning of testicular somatic cells. It is the androgens, primarily testosterone, which act through the somatic cells to regulate germ cell differentiation. Despite extensive research in this area, little is known about the cell-specific requirements for androgens and even less is understood about the downstream effectors of androgen signalling. However, recent work using cell-specific ablation of androgen receptor function has demonstrated a clear requirement for androgen signalling at multiple, discrete time points during spermatogenesis. These models also provide useful tools for identifying the targets of androgen receptor activity. The purpose of this review is to provide a brief overview of recent advances in our understanding of hormonal regulation of spermatogenesis, with an emphasis on the role of testosterone within the testis, and to pose important questions for future research in this field.

Testicular toxicity induced in dogs by nefiracetam, a neutrotransmission enhancer

To investigate mechanisms of the testicular toxicity of nefiracetam and to find sensitive parameters to predict the toxicity, male beagle dogs were orally administered 180 or 300 mg/kg per day of the drug once and for 1 and 4 weeks. Time-course changes in serum and/or testicular hormone levels and semen parameters, and testicular morphology were examined. The testicular testosterone level was decreased 4 h after single administration of nefiracetam at 300 mg/kg per day, but the progesterone level showed no change at that time. The serum testosterone level was decreased after single, 1-week or 2-week treatment. In contrast, the serum estradiol level was increased from 1- to 4-week treatment. No changes in serum LH, FSH and inhibin B levels were observed throughout the experimental period. Decreased sperm motility and increased number of malformed sperms were first observed in semen after 4-week treatment. Histopathological examination of the testis revealed moderate and severe seminiferous atrophy with multinucleated giant cell formation at 180 and 300 mg/kg per day, respectively, after 4-week treatment, but not 1-week treatment. These results show that nefiracetam decreases testicular testosterone level in dogs following single oral administration of a high dose, and induces severe morphologic changes after 4-week treatment. This reduction is shown to be a sensitive parameter to detect the toxicity, and is suggested to be induced by the impaired conversion of progesterone to testosterone in Leydig cells.

Sequential analysis of testicular lesions and serum hormone levels in rats treated with a Psoralea corylifolia extract

In order to clarify pathogenetic targets for the testicular toxicity of a extract of Psoralea corylifolia (P. corylifolia), F344 rats were fed diet containing 3% P. corylifolia extract for up to 12 weeks and subjected to hormone assays and histopathological examination on the testis and epididymis at weeks 1, 2, 4, 8 and 12 (Exp 1). Similar analyses were performed on 1, 3, 7 and 14 days after a single gavage administration of the P. corylifolia extract at a dose of 10 g/kg b.w. (Exp 2). In Exp 1, increase in the numbers of degenerated and exfoliated germ cells and loss of elongated spermatids beyond steps 7 or 8 were initially observed in the seminiferous tubules at week 1, followed by more pronounced degeneration of germ cells with depletion of post-meiotic populations from week 2. The tubular degeneration was associated with Leydig cell atrophy and persistent reduction of serum testosterone and FSH levels throughout the treatment period and a slight reduction of serum LH in later stages. In Exp 2, reduction of serum testosterone and FSH levels preceded degeneration of germ cells in stage VII and VIII tubules at 3 and 7 days after the administration. The results suggest that rapid androgen deprivation reflecting direct interference with Leydig cell function and simultaneous disturbance of the pituitary-testicular axis play pivotal roles in P. corylifolia extract-induced germ cell injury in seminiferous tubules.

A Sertoli cell-selective knockout of the androgen receptor causes spermatogenic arrest in meiosis

Androgens control spermatogenesis, but germ cells themselves do not express a functional androgen receptor (AR). Androgen regulation is thought to be mediated by Sertoli and peritubular myoid cells, but their relative roles and the mechanisms involved remain largely unknown. Using Cre/loxP technology, we have generated mice with a ubiquitous knockout of the AR as well as mice with a selective AR knockout in Sertoli cells (SC) only. Mice with a floxed exon 2 of the AR gene were crossed with mice expressing Cre recombinase ubiquitously or selectively in SC (under control of the anti-Müllerian hormone gene promoter). AR knockout males displayed a complete androgen insensitivity phenotype. Testes were located abdominally, and germ cell development was severely disrupted. In contrast, SC AR knockout males showed normal testis descent and development of the male urogenital tract. Expression of the homeobox gene Pem, which is androgen-regulated in SC, was severely decreased. Testis weight was reduced to 28% of that in WT littermates. Stereological analysis indicated that the number of SC was unchanged, whereas numbers of spermatocytes, round spermatids, and elongated spermatids were reduced to 64%, 3%, and 0% respectively of WT. These changes were associated with increased germ cell apoptosis and grossly reduced expression of genes specific for late spermatocyte or spermatid development. It is concluded that cell-autonomous action of the AR in SC is an absolute requirement for androgen maintenance of complete spermatogenesis, and that spermatocyte/spermatid development/survival critically depends on androgens.

Androgen receptor function is required in Sertoli cells for the terminal differentiation of haploid spermatids

Androgen receptor function is required for male embryonic sexual differentiation, pubertal development and the regulation of spermatogenesis in mammals. During spermatogenesis, this requirement is thought to be mediated by Sertoli cells and its genetic and pharmacological disruption is manifested in spermatocytes as meiotic arrest. Through studies of a hypomorphic and conditional allele of the androgen receptor (Ar) gene, we have uncovered a dual post-meiotic requirement for androgen receptor activity during male germ cell differentiation. Observations in Ar hypomorphic animals demonstrate that terminal differentiation of spermatids and their release from the seminiferous epithelium is AR dependent and maximally sensitive to AR depletion within the testis. Cell-specific disruption of Ar in Sertoli cells of hypomorphic animals further shows that progression of late-round spermatids to elongating steps is sensitive to loss of Sertoli cell AR function, but that progression through meiosis and early-round spermatid differentiation are surprisingly unaffected.

Ultrastructural changes induced by leaves of Azadirachta indica (Neem) in the testis of albino rats

The present work was designed to study the effect of Azadirachta indica (Neem) powder on rat testis using the electron microscope. Male albino rats received 100 mg each A. indica leaf powder orally (by gavage). On alternate days, a second group of rats received 0.125 mg testosterone dipropionate intramuscularly. A third group received both A. indica leaf powder by gavage and testosterone dipropionate intramuscularly. Suitable controls were maintained. After autopsy, ultrastructural analysis of the testis revealed that animals treated with testosterone dipropionate showed well-developed Sertoli cells and germ cells with well-developed cytoplasmic organelles. By contrast, in A. indica-treated rats, intracellular spaces and vacuolization were observed in Sertoli cells; whereas in Leydig cells, cytoplasmic inclusions appeared diminished, and the configuration of granular endoplasmic reticulum appeared as a single unbranched tubule. In late spermatids, defects were observed in the mitochondrial sheath. The ultrastructural changes seen in the A. indica-treated group provide a clue that A. indica leaves might affect spermatogenesis through antispermatogenic and antiandrogenic properties.

Investigation of testicular toxicity of nefiracetam, a neurotransmission enhancer, in rats

Testicular toxicity of nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide), a neurotransmission enhancer, was investigated in male Slc:SD rats. Nefiracetam was orally administered daily at 1500 mg/kg for 4 weeks, and the animals were killed sequentially during the course of administration to determine testicular histopathological changes and sperm head counts (SHC), and hormonal changes. Retention of step 19 spermatids, sporadic degeneration of pachytene spermatocytes and step 7 spermatids in the stage VII seminiferous tubules, and a decrease in SHC were seen as earliest changes after 1 week of administration. These changes gradually advanced up to atrophy of seminiferous tubules with multinucleated-giant-cell formation after 4-week administration. Serum and testicular testosterone levels were decreased, but recovered to the control levels within a day following a single administration, and the decreases were repeated after 1-week administration. These results suggest that nefiracetam-induced earliest changes could be caused by the decreased level of testicular testosterone.

Neonatal estrogen exposure of male rats alters reproductive functions at adulthood

The effects of neonatal exposure to different doses of diethylstilbestrol (DES) on the reproductive functions of male rats at adulthood were evaluated. Sprague-Dawley rats (5-8/group) received sc injections of 25 microl olive oil containing DES (Sigma Chemical Co., St. Louis, MO) at a dose of 10 microg, 1 microg, 100 ng, 10 ng, or 1 ng per rat on alternate days from Postnatal Days 2-12. Control animals received olive oil only. All animals were allowed to develop until 83-91 days of age; however, when they were 70 to 80 days old, four male rats each from the 10 microg, 1 microg, 100 ng, and control groups were cohabited with untreated 60- to 70-day-old females (1:1) for 12 days. At the end of cohabitation, both mated and unmated male rats were weighed, and blood and tissue samples were collected and processed. Results revealed that although sperm motility patterns and sperm morphology were adversely affected in the 10- microg group, other reproductive parameters, including 1). daily sperm production (DSP)/testis; 2). absolute and relative weights of the testis, epididymis, and seminal vesicle; and 3). sperm numbers in both regions of the epididymis declined significantly in a dose-dependent manner in the 10- and 1- microg groups. Conversely, in the <1- microg groups, none of these parameters (except DSP/testis and weight of the epididymis in the 100-ng group, and sperm numbers in the epididymis of the 100- and 10-ng groups) was different from controls. Generally, plasma testosterone levels decreased in the 10- and 1- microg groups, FSH level increased in the 10-microg group, and prolactin and LH levels were unaltered. In the fertility study, although each male in the 1-microg, 100-ng, and control groups produced a copulatory plug and impregnated a female, none could do so in the 10-microg group. The mean number of pups per litter was reduced to eight in the 1-microg group, in contrast to 15 each in the 100-ng and control groups. In conclusion, exposure of neonatal male rats to DES altered sperm motility patterns, sperm fertility (as evident from the reduced number of pups in the 1-microg group), and sexual behavior (as evident from the absence of copulatory plugs in the 10-microg group) and reduced weights of reproductive organs, DSP/testis, and sperm numbers in the epididymis. Whether these alterations/reductions persist in older rats (6-8 mo of age) is under investigation.

Methoxyacetic acid disregulation of androgen receptor and androgen-binding protein expression in adult rat testis

Chemical agents can disrupt the balance between survival and apoptosis during spermatogenesis and thus give rise to reduced counts of spermatozoa (oligospermia). One such agent that produces significant germ cell apoptosis at specific stages of the cycle of the seminiferous epithelium is methoxy acetic acid (MAA), the active metabolite of a commonly used solvent, methoxyethanol. Although MAA gives rise to apoptosis of pachytene spermatocytes, it is not known whether MAA exerts a direct effect on germ cells or whether it also affects other testicular cell types such as the Sertoli cells. In the present investigation, we tested the hypothesis that MAA has direct effects on Sertoli cells in vivo. In MAA-treated rats, stage-specific expression of androgen receptor (AR) protein in Sertoli cells was significantly altered, as determined by AR immunohistochemistry. In MAA-treated animals, high AR expression was found in Sertoli cells coincident with the MAA-induced apoptosis of late-stage pachytene spermatocytes. The altered expression of AR in MAA-treated animals was also seen in seminiferous tubules harvested by laser capture microdissection. In addition to effects on AR expression, androgen-binding protein (ABP) mRNA levels were also altered in a stage-specific manner. Using a different system for mouse Sertoli cell lines TM4 and MSC-1, positive for either AR or ABP, respectively, we found a direct effect of MAA on ABP protein and mRNA expression in the MSC-1 cell but did not detect an effect on AR protein or mRNA expression in TM4 cells. Mouse fibroblasts that express endogenous AR were stably transfected with two AR promoter/reporter systems (MMTV-CAT and probasin-luciferase, respectively). We used these fibroblasts to examine the ability of MAA to potentiate dihydrotestosterone (DHT) activation of AR. Although MAA did not activate AR directly, it did potentiate DHT activation of the AR by 2- to 4-fold. MAA altered the expression level of AR and ABP in vivo and increased AR transcriptional activity in tissue culture cells. The abnormal spermatogenesis generated by MAA is at least partly due to direct effects on Sertoli cells. It is still unclear whether MAA elicits a proapoptotic signal from Sertoli cells or diminishes a prosurvival signal required by germ cells downstream to altering AR and ABP expression in a stage-specific fashion.

DNA repair gene Ercc1 is essential for normal spermatogenesis and oogenesis and for functional integrity of germ cell DNA in the mouse

Ercc1 is essential for nucleotide excision repair (NER) but, unlike other NER proteins, Ercc1 and Xpf are also involved in recombination repair pathways. Ercc1 knockout mice have profound cell cycle abnormalities in the liver and die before weaning. Subsequently Xpa and Xpc knockouts have proved to be good models for the human NER deficiency disease, xeroderma pigmentosum, leading to speculation that the recombination, rather than the NER deficit is the key to the Ercc1 knockout phenotype. To investigate the importance of the recombination repair functions of Ercc1 we studied spermatogenesis and oogenesis in Ercc1-deficient mice. Male and female Ercc1-deficient mice were both infertile. Ercc1 was expressed at a high level in the testis and the highest levels of Ercc1 protein occurred in germ cells following meiotic crossing over. However, in Ercc1 null males some germ cell loss occurred prior to meiotic entry and there was no evidence that Ercc1 was essential for meiotic crossing over. An increased level of DNA strand breaks and oxidative DNA damage was found in Ercc1-deficient testis and increased apoptosis was noted in male germ cells. We conclude that the repair functions of Ercc1 are required in both male and female germ cells at all stages of their maturation. The role of endogenous oxidative DNA damage and the reason for the sensitivity of the germ cells to Ercc1 deficiency are discussed.

Dose-dependent response to an intratesticular injection of calcium chloride for induction of chemosterilization in adult albino rats

This study concerned the minimum and optimum effective doses of calcium chloride needed for induction of chemosterilization in male albino rats, 30 days after a single intratesticular injection of calcium chloride (CaCl2.2H2O) solution at 2.5, 5, 10 or 20 mg per 100 g body weight per testis. There was a significant diminution in the relative wet weight of the sex organs (p<0.01), epididymal sperm count (p<0.001), plasma concentration of testosterone (p<0.01), testicular activities of delta5,3beta-hydroxy steroid dehydrogenase (delta5,3beta-HSD), 17beta-hydroxy steroid dehydrogenase (17beta-HSD) (p<0.01), glutathione S-transferase (GST) (p<0.01), superoxide dismutase (SOD) (p<0.01), and peroxidase (p<0.01), significant elevations in testicular content of malondialdehyde (MDA) and conjugated dienes (p<0.01), along with derangement of seminiferous tubular architecture and degeneration of the Leydig cells in the testis and elevations in the concentrations in the plasma of LH and FSH (p<0.01), commencing at a dose of 5 mg, with the greatest effects at a dose of 20 mg. No significant alterations in these factors occurred at the dose of 2.5 mg in comparison to the control that received only the vehicle. There was no significant alteration in the plasma concentrations of prolactin (p>0.05), corticosterone (p>0.05) or fasting blood glucose or in the rectal temperature (p>0.05) at any of the doses relative to the control group, suggesting that this chemosterilizing procedure did not exert any chronic stress on the experimental animals. From these observations, it may be suggested that 5 mg should be considered as the minimum dose, and 10 mg or 20 mg as the optimum dose, whereas 2.5 mg was ineffective for induction of chemosterilization. There would seem to be little point in using more than 20 mg of calcium chloride for this purpose. Intratesticular injection of calcium chloride at an effective dose may be considered as an alternative to surgical castration.

Activating signal cointegrator 1 is highly expressed in murine testicular Leydig cells and enhances the ligand-dependent transactivation of androgen receptor

Activating signal cointegrator 1 (ASC-1) has been recently reported as a coactivator of some nuclear receptors. In the present study, we have analyzed the expression of ASC-1 in the mouse testis and investigated its capacity to modulate the transcriptional activity of androgen receptor (AR). We found that although ASC-1 mRNA was ubiquitously expressed at a low level in mouse tissues, a couple of testis-specific mRNAs were expressed in the adult testis. Cloning of one testis-specific variant revealed that the ubiquitous and testis-specific transcripts of ASC-1 share at least the same open reading frame. The expression of the testis-specific ASC-1 mRNAs was developmentally regulated, and the onset of their expression coincided with the initiation of spermatogenesis. In situ hybridization of mouse testis with ASC-1 antisense probe demonstrated predominant expression of ASC-1 in the interstitial Leydig cells that express AR. Moreover, yeast two-hybrid tests and glutathione S-transferase pull-down assays revealed that ASC-1 associates directly with AR and that the hinge domain of AR and a putative zinc-finger motif of ASC-1 are major determinants for their interaction. Transient transfection assays performed by expressing ASC-1 in combination with AR and an androgen-responsive reporter gene showed that ASC-1 moderately alters the induction of the reporter gene. Taken together, these results suggest that ASC-1 may function as an AR coregulator and have a role in testicular functions.

Gonadal toxicity of an ethanol extract of Psoralea corylifolia in a rat 90-day repeated dose study

Ethanol extracts of seeds of Psoralea corylifolia are proposed as food additives for processed food preservation. An extract was administered by admixing into diet at concentrations of 0, 0.375, 0.75, 1.5 or 3.0% to 10 male and 10 female F344 rats each for 90 days to evaluate its toxicity. Body weight gain, food consumption and food conversion efficiency (body weight gain per food consumption) were lower in the extract-treated animals, except for the 0.375% males, as compared to the control animals. Absolute and/or relative testes weights in the 1.5 and 3.0% groups and those of ovaries in the 3.0% group were significantly (p < 0.01) lower than in the control group. On histopathological examination, seminiferous tubular atrophy and Leydig cell atrophy in the testes, and epithelial cell atrophy in the seminal vesicles and prostate were observed in the 1.5 and 3.0% males. Decrease in the number of corpora lutea associated with frequent necrotic follicles in the ovaries in the 1.5 and 3.0% females and less frequent endometrial glands in the uterus in the 3.0% females were also detected. These results might suggest disruption of the hypothalamus-pituitary-gonadal axis in Psoralea corylifolia-treated rats as possible mechanisms underlying this gonadal toxicity.

Effect of compound CDRI 84/35 and synthetic estrogen on the seminiferous epithelium of immature rat

Compound CDRI 84/35 (a piperazine derivative--a potent antispermatogenic agent) has been shown to cause significant inhibition in testicular spermatogenesis without affecting Leydig cell and accessory sex organ function in adult rats. The present study was conducted to determine its effect on the germ cell population and Leydig cell morphology in immature rats (40-50 gm) administered CDRI 84/35 (100 mg/kg/day p.o.), synthetic estradiol benzoate (EB; 5 microg/rat/day) and vehicle at the age of 21 days. Animals were killed 24 h later following 7 and 14 days' treatments. Bouin's fixed testes were sectioned (at 5 microm) and stained with PAS-hematoxylin. Quantitative determination of Sertoli Cell-Germ Cell ratio was carried out in 150 round seminiferous tubules in each group of 5 rats. Results revealed a significant decrease in number of the spermatocytes (non-pachytene and pachytene) and early (round) spermatids in step 1-8 of spermiogenesis without affecting Leydig cell morphology in rats administered CDRI 84/35 for 7 and 14 days as compared to corresponding controls. In contrast, the testes of rats injected with synthetic EB, caused a marked inhibition in these meiotic and post-meiotic germ cell types, as well as in the diameters of round seminiferous tubules, and Leydig cells nuclei (only in 14 days treatment), and testicular weight on autopsy days 8 and 15 as compared to CDRI 84/35-treated rats. While the number of pre-meiotic spermatogoniae was observed to be slightly decreased after only 14 days treatment in both CDRI 84/35 and EB treatment groups, the Sertoli cell number did not show any significant change as compared to controls. The present investigation confirms the antispermatogenic effect of compound CDRI 84/35 in immature rats similar to that reported in adult rats. Marked inhibition in pachytene spermatocytes and other testicular parameters following synthetic estrogen treatment might be due to its antiandrogenic action, contrasting with the non-hormonal profile of CDRI compound.

Diethylstilbestrol-treated adult rats with altered epididymal sperm numbers and sperm motility parameters, but without alterations in sperm production and sperm morphology

In this study, we characterized estrogenic effects of diethylstilbestrol (DES) on reproductive parameters in male rats to identify a minimal dose level that alters epididymal and sperm functions but has little or no effect on sperm production and/or spermatogenesis. Adult rats (five animals/group) received s.c. injections of 0.2 ml of corn oil containing DES at a rate of 1.0 mg, 200 microg, 40 microg, 8 microg, 1.6 microg, or 320 ng x rat(-1) x day(-1) for 12 days. The control group received corn oil only. DES effects were similar in the 8-microg group and higher dose groups and included significant (P < or = 0.05) reductions in 1) absolute and relative weights of the head and body of the epididymis (EP), tail of the EP, and seminal vesicle, 2) numbers of sperm in both regions of the EP, and 3) motility characteristics in sperm collected from the tail of the EP. Conversely, no significant changes were observed in relative testis weight, daily sperm production, spermatogenesis, seminiferous epithelial height in stage VII, and sperm morphology. All of the above parameters in the 1.6-microg group (except seminal vesicle weight) and 320-ng group were comparable to those of controls. Plasma testosterone (T) level was reduced to an almost undetectable level in the > or = 8-microg groups and to a very low level in the 1.6-microg group (0.35 vs. 2.36 ng/ml in controls or 320-ng group), but LH level was unaltered. In a parallel fertility study, males received DES at a rate of 40, 8, or 1.6 microg x rat(-1) x day(-1) for 12 days prior to and 12 days during cohabitation (1:1) with untreated females. Of the 15 females cohabited with treated males (5 females/dose), none in the 40-microg and 8-microg groups and 1 in the 1.6-microg group formed a copulatory plug and delivered 8 pups, in contrast to 5/5 copulatory plugs and 13-15 pups/litter in the controls. DES at a rate of 8 microg x rat(-1) x day(-1) for 12 days reduced EP weights, sperm numbers in the EP, and sperm motility patterns but caused minimal to no alterations in daily sperm production, spermatogenesis, or sperm morphology. Factors other than T, or in addition to lower T, may be responsible for DES-induced reproductive disorders (despite lower T, sperm contents and sperm motility patterns in the EP were normal in the 1.6-microg group). Deficits in EP sperm functions and/or sexual behavior (as evident from absence of copulatory plugs) probably accounted for reduced fertility in treated males.

Pathogenesis of male reproductive toxicity

Toxicologic disturbance of male reproductive function can occur at many sites and produce a range of effects, some primary and some secondary to the initial insult. The challenge to the toxicological pathologist is to identify the primary site of damage and provide an insight into the pathogenesis of the morphologic lesion or functional deficit. Target sites include the testis, the epididymis, the mature sperm, and the hormonal regulatory system. Detection of effects at these varied sites requires the measurement of multiple endpoints only 1 of which is histopathology, but once identified, careful microscopic examination of the early changes in lesion development can provide essential information on the probable target cell and possible mechanisms of toxicity. Chemicals that affect different cell types or specific cellular functions generally elicit predictable patterns of pathological changes that can be readily recognized. Understanding the pathogenesis, the likely reversibility and the significance of reproductive tract lesions is aided by a sound knowledge of the physiology of the testis and epididymis and, in particular, an understanding of the timing of sperm production and transport.

Role of Sertoli cells in injury-associated testicular germ cell apoptosis

This review examines experimental models of Sertoli cell injury resulting in germ cell apoptosis. Since germ cells exist in an environment created by Sertoli cells, paracrine signaling between these intimately associated cells must regulate the process of germ cell death. Germ cell apoptosis may be signaled by a decrease in Sertoli cell pro-survival factors, an increase in Sertoli cell pro-apoptotic factors, or both. The different models of Sertoli cell injury indicate that spermatogenesis is susceptible to disruption, and that targeting critical Sertoli cell functions can lead to rapid and massive germ cell death.

Molecular basis of androgen receptor diseases

androgens act through a single intracellular androgen receptor (AR) which is encoded by a single-copy gene in the X chromosome. Disruption of the AR by genetic mutation results in complete androgen insensitivity syndrome (CAIS) and the female phenotype in otherwise healthy 46XY individuals. Although CAIS is the best known phenotype, recent studies from our laboratory and elsewhere show that malfunction of the AR is associated with many androgen-regulated diseases or conditions that cross traditional clinical disciplines ranging from paediatrics (ambiguous genitalia), gynaecology (primary amenorrhoea), urology (prostate cancer), neurology (spinal bulbar muscular atrophy), reproductive medicine (male infertility), orthopedics (rheumatoid arthritis), oncology (breast cancer) and dermatology (hirsutism, baldness and acne). Of particular interest are the roles that polymorphic CAG trinucleotide repeat tracts and subtle mutations in the AR ligand-binding domain have in the aetiology of male infertility and prostate cancer, two conditions affecting large numbers of patients. Novel mechanisms of pathogenesis have been uncovered in these cases, and they involve defective protein-protein interactions with coregulator molecules such as TIF2 (transcriptional intermediary factor 2). Knowledge of the critical role that the AR plays in the pathogenesis of these diverse conditions has led to improved diagnostic methods and successful therapy.

Epididymal sperm motion as a parameter of male reproductive toxicity: sperm motion, fertility, and histopathology in ethinylestradiol-treated rats

The present study was designed to characterize the effect of ethinylestradiol (EE) on epididymal sperm motion using a computer-assisted sperm analysis system (CASA), and to elucidate the correlation between sperm motion endpoints and other measures including fertility, histopathologic, and endocrinologic endpoints. EE was orally given to adult male rats at a daily dosage of 10 mg/kg for 3 and 5 d, and at daily dosages of I and 10 mg/kg for 1, 2, 3, and 4 weeks. Changes in sperm motion were first detected after one week of treatment. Of nine sperm motion parameters, the percentage of motile sperm, velocity, and amplitude of the lateral head displacement (ALH) were decreased in the 10 mg/kg dosing group. Accompanying the decreases in those parameters, the male fertility indices in the 10 mg/kg dosing group were reduced after one week of treatment, and no males in this group could impregnate intact females after 2 weeks or more of treatment. The number of sperm heads in the cauda epididymis in the 10 mg/kg dosing group was reduced to about one-half that in the control group after one week of treatment, whereas the total number of homogenization-resistant advanced spermatids in the testis was not altered and only a slight change was detected in the number and morphology of germ cells in the testis. These results suggest that reduction in the number of epididymal sperm and in sperm motion are not secondary to testicular alteration. However, after 3 weeks of treatment, the number of sperm heads in the testis was drastically reduced with severe atrophy of the seminiferous tubules both in the 1 and 10 mg/kg dosing groups. The profiling of epididymal luminal fluid proteins indicated that two major bands that migrated with molecular weights of about 22 and 23 kDa were weakened and their density was reduced to approximately 70% of the control after 5-d and one week treatments in the 10 mg/kg dosing group. Circulating testosterone declined drastically after 3 d of treatment and remained at undetectable levels with a concomitant decline of circulating LH and FSH, suggesting that EE inhibits testosterone secretion immediately via a negative feedback system, and there follow changes in the accessory reproductive organs including the epididymis. These results indicate that EE affects epididymal spermatozoa before testicular germ cells via a testosterone deficiency, when it is administered at extremely high dosages. The reduction in the sperm motion manifested as decreases in the percentage of motile sperm, ALH, and velocity, is considered to be responsible for the onset of infertility. Sperm motion analysis could be particularly useful for detecting the toxic effects of chemicals that act through the endocrinologic system on the epididymis.

Synergistic action of steroids and spermatocele fluid on in vitro proliferation of prostate stroma

PURPOSE

Our goal is to understand human prostate growth phenomena potentially important to BPH development and growth. The objective of the present study is to characterize in vitro prostate stromal proliferative factors in testis epididymal secretions.

MATERIALS AND METHODS

Human spermatocele fluids were used as a source of testicular epididymal plasma (STEP). Primary cultures of human prostate stromal cells were routinely grown in RPMI-1640 with 10% fetal bovine serum. During a 6-day experimental period, cells were cultured in RPMI-1640 in the absence of serum but supplemented with ITS. Whole STEP, ether stripped STEP, or heparin affinity column treated STEP was included in the culture medium with and without the addition of testosterone (T), dihydrotestosterone (DHT), or estradiol (E). Results of these treatments were assessed by cell counts. Antibodies against smooth muscle myosin heavy chain, smooth muscle alpha actin, and prolyl-4-hydroxylase were utilized in immunocytochemical characterization of cultured cells.

RESULTS

Whole STEP stimulated prostatic stromal cells derived from prostates of 15, 45, 70 and 72-year-old men. Treatment of STEP by ether stripping or heparin affinity column exposure did not result in a significant reduction in cell counts. With the exception of the 15-year-old specimen, addition of T or DHT to ether stripped STEP resulted in a significant increase in cell counts over that of ether stripped STEP treatment alone. Preliminary immunocytochemical evaluation indicated the presence of variable mixture of fibroblasts, myofibroblasts, and smooth muscle cells in these cultures.

CONCLUSIONS

These in vitro observations indicate that testis epididymal secretions contain androgen/STEP synergistic and androgen independent STEP factors promoting prostate stromal growth. These factors are not heparin binding. These observations are consistent with the concept that, in addition to the production of steroids, the testis produces non-androgenic factors that act in concert with, as well as independently of, androgen to stimulate prostatic growth.

Apoptosis precedes detachment of germ cells from the seminiferous epithelium after hormone suppression by short-term oestradiol treatment of rats

Spermatogenesis is a highly synchronized process in which FSH and testosterone are considered the major regulators. Nevertheless, the mechanism by which these hormones act on germ cells is unclear. Cell adhesion has been proved to play an essential role in the regulation of programmed cell death in epithelial cells and it is now known that FSH and testosterone withdrawal results in the triggering of apoptosis as well as germ cell detachment from the seminiferous epithelium. Therefore, it seemed important to investigate whether the triggering of apoptosis in germ cells by experimental hormone suppression occurred as a result of their previous detachment from the epithelium. To achieve this goal, adult male rats were injected with 50 micrograms oestradiol benzoate for 1, 2, 3, 4, 5 or 10 days to suppress gonadotrophin secretion and thus intratesticular levels of testosterone. Germ cell apoptosis was assessed in testes from these animals by in situ 3' end-labelling of DNA fragments and quantified in seminiferous tubule sections at stages VII-VIII. Serial sections throughout the epididymides from these animals were analysed to search for immature germ cells detached from the epithelium. These cells were scored and quantified in non-consecutive randomly selected epididymal sections. Our data indicate that the triggering of apoptosis in germ cells precedes germ cell detachment, suggesting that detachment of germ cells from the epithelium, occurring after hormone suppression, is not necessary for germ cell apoptosis.

A delta 4-3-keto pathway for testosterone synthesis in the human spermatozoa

The ability of human spermatozoa to metabolize pregnenolone to progesterone and progesterone to testosterone was assessed. Sonicated specimens of freshly ejaculated sperm from two groups of husbands (n = 6, age 32-38 years; n = 6, age 30-51 years) of infertile couples in the range of sperm concentration between 237.5 and 568.5, 100.1 and 248.8 millions per ejaculate, were separately incubated with [7n-3H]pregnenolone and [1,2,6,7,16,17-3H]progesterone. Using the classical reverse-isotope dilution technique the desired products [3H]progesterone and [3H]testosterone formed from the respective substrates were isolated and characterized, yielding 1.4 to 12.2% and 3.1 x 10(-2) to 2.0 x 10(-1)%. Such metabolites were not evident in the controls. The results indicate that the human spermatozoa contain the enzymes necessary for the transformation of pregnenolone to testosterone via the delta 4-3-keto route.

The effects of pre- and postnatal exposure to the nonsteroidal antiandrogen flutamide on testis descent and morphology in the Albino Swiss rat

Exposure of male Albino Swiss rats to the nonsteroidal antiandrogen flutamide during the period from gestational day (d) 10 to birth resulted in feminisation of the external genitalia and the suppression of growth of the male reproductive tract. In adulthood, testes were found to be located in diverse positions. True cryptorchidism occurred in 10% of cases, whereas 50% of testes descended to the scrotum and 40% were located in a suprainguinal ectopic region. Varying degrees of tubule abnormality were seen in the testes of flutamide-treated animals, ranging from completely normal tubules with full spermatogenesis (and the expected frequency of the stages of spermatogenesis) to severely abnormal tubules lined with Sertoli cells only. For each individual testis, the overall severity of tubule damage was strongly correlated with its adult location, with intra-abdominal testes worst affected and scrotally-located testes least; only the latter contained normal tubules. Similarly, intra-abdominal testes were the smallest in weight and contained the least testosterone. By contrast, postnatal treatment of male rats with flutamide from birth to postnatal d 14 did not impair development of the external genitalia, the process of testicular descent or adult spermatogenesis. These findings confirm that androgen blockade during embryonic development interferes with testicular descent but also demonstrate that (1) prenatal flutamide treatment per se has a detrimental effect on adult testis morphology but (2) the degree of abnormality of the testes is strongly influenced by location.

Evaluation of testicular toxicity in safety evaluation studies: the appropriate use of spermatogenic staging

Toxicology of the male reproductive system has received increased interest in recent years partly fuelled by the growing reports of falling sperm counts and rising reproductive disorders in the human population. Recently revised regulatory guidelines for the safety assessment of pharmaceuticals and chemicals on reproduction and fertility have emphasized the importance of detailed histopathological examination of the testes as a sensitive method for detecting disturbances in spermatogenesis. Unfortunately this has been accompanied by a general confusion regarding a practical approach to undertaking such a detailed examination, particularly in respect to the use of spermatogenic or tubular staging to identify subtle disturbances in spermatogenesis. The ability to identify tubular stages of the spermatogenic cycle in sections of testis plus a good understanding of the spermatogenic process and its dynamics are essential in order to carry out a sensitive of testicular histopathology and to interpret the changes seen. A rational approach is required initially to detect and subsequently to characterize toxic effects to the male reproductive system. It is important that a distinction is made between these two objectives since different study designs are required and different methodology may be employed to produce the type of information or data required.

Recognition of phosphatidylserine on the surface of apoptotic spermatogenic cells and subsequent phagocytosis by Sertoli cells of the rat

In a primary co-culture of spermatogenic and Sertoli cells of the rat, many spermatogenic cells die by apoptosis and are subsequently engulfed by Sertoli cells. We investigated the mechanism of this phagocytosis reaction. Testicular cells from 20-day-old rats were cultured, and spermatogenic cells and Sertoli cells were separated. When the recovered spermatogenic cells were maintained without Sertoli cells, the viability of the cells decreased and they became more susceptible to phagocytosis by Sertoli cells. Phagocytosis was severely impaired when liposomes containing acidic phospholipids, such as phosphatidylserine, phosphatidylinositol, and cardiolipin, were included in the reaction, whereas those consisting of neutral phospholipids showed little effect. Such anionic liposomes were more efficiently engulfed by Sertoli cells than were the other neutral liposomes. Also, the number of spermatogenic cells that exposed phosphatidylserine to the surface increased when cells were maintained in single culture. The results indicate that upon induction of spermatogenic cell apoptosis, phosphatidylserine and probably other acidic phospholipids, which are normally localized in the inner leaflet of the plasma membrane, translocate to the outer leaflet and serve as a signal for phagocytosis by Sertoli cells.

Characterization of a delta 5-3 beta-hydroxy pathway of testosterone synthesis in the human spermatozoa

Sonicated specimens of freshly ejaculated sperm from two groups of husbands (n = 6, age 32-38 years; n = 7, age 27-38 years) of infertile couples in the range of sperm concentration between 237.5 and 568.5; 131.1 and 256.7 millions per ejaculate were separately incubated with [7n-3H]pregnenolone and [1,2,6,7(-3)H]dehydroepiandrosterone. Using the reverse-isotope dilution technique [3H]dehydroepiandrosterone and [3H]testosterone formed from the respective substrates were isolated and characterized, yielding 1.2 x 10(-2) to 4.6 x 10(-20/0) and 7.1 x 10(-2) to 2.5 x 10(-10/0)/ Such metabolites were not evident in the controls. These results provide evidence for metabolic transformation of pregnenolone to testosterone via the delta 5-3 beta-hydroxy route.

Induction of apoptotic cell death in the seminiferous tubule of the adult rat testis: assessment of the germ cell types that exhibit the ability to enter apoptosis after hormone suppression by oestradiol treatment

The involvement of apoptosis in germ cell degeneration in the adult rat testis after gonadotrophin suppression has recently been shown in several studies, which have focused on the localization of apoptotic cells to the stages of the spermatogenic cycle. However, the precise germ cell types and maturing steps at which apoptosis is elicited remain controversial. The present study used oestradiol treatment to produce hormone suppression and to study induced germ cell degeneration. Adult male rats were administered a daily injection of 50 micrograms oestradiol benzoate for 5, 10 or 15 days. Characterization of the ultrastructural features of the dying cells and in-situ 3'-end labelling of DNA showed clearly that the deaths of all the germ cell types occurred by apoptosis. High-resolution light microscopy, although time-consuming, resulted in a precise method for analysis of the localization of the cells involved. Stages IV-X of the seminiferous epithelium were found to be the most sensitive to degeneration in response to oestradiol treatment. Our results are discussed in the light of current knowledge about the hormonal control of the spermatogenic cycle. Oestradiol treatment has proved to provide a suitable in-vivo model to study germ cell death.

Further observations on the early events that contribute to establishing the morphological pattern shown by the oestradiol suppressed testis

The analysis of the morphological response of the seminiferous epithelium to hormone suppression after hypophysectomy has been widely used in the study of spermatogenesis. Unlike hypophysectomy, which causes a sharp fall in gonadotropin levels, oestradiol treatment, although mimicking its effects, leads to a partial and progressive hormone suppression. We have chosen this model in order to clarify further the early morphological response of the seminiferous epithelium to hormone suppression. For this purpose, adult male rats, injected daily from 1-35 days with 50 micrograms oestradiol benzoate, were analyzed. Our observations showed that cell sloughing was the main cause of germ cell depletion in the oestradiol treated testis. After 17-18 days treatment, massive sloughing affected nearly all the germinal cells, but the correct synchronization of mitoses, meiosis and spermatid differentiation along the 14 stages of spermatogenesis was always well kept. Quantitative analysis showed that spermatogenic wave was well preserved in the oestradiol-treated animals and that sloughing was a stage-independent phenomenon.

Macro, micro, and molecular research on spermatogenesis: the quest to understand its control

Synchronous maturation of the germ cells in the seminiferous epithelium has long been recognized by microscopy, and is believed to be a consequence of a complex interaction between the germ cells and the Sertoli cells, largely driven by testosterone and its synergistic action with follicle-stimulating hormone. Overall coordination of the cycle of the seminiferous epithelium is reviewed with regard to the known and possible actions of testosterone upon the Sertoli cells and the germ cells. With gradual refinements of optical instrumentation and development of a wide range of histological, morphometric, biochemical, and molecular techniques, coupled with selective alterations of hormonal stimulation and the cellular composition of the testis, new approaches to the question of how sperm production is regulated are becoming available. Germ cell and Sertoli cell functions are intimately related to each other via local, intratesticular or paracrine signals which are suppressed or triggered at certain defined steps in the spermatogenic process. The coordination of germ cell proliferation and maturation is discussed in terms of the contributions made by microscopical techniques.

Effect of testosterone on cisplatin-induced testicular damage

The present study investigated whether testosterone supplementation overcame testicular damage caused by cisplatin. A group of Wistar rats was given 8 mg cisplatin/kg body weight, another group was given cisplatin plus testosterone, and a third group was given the vehicle only. Animals were sampled after 5 days and testicular cells were scored at stage VII of the seminiferous epithelial cycle to measure drug-induced damage. Preleptotene primary spermatocytes and step 7 and step 19 spermatids were significantly reduced in number in the cisplatin group by 21, 20, and 28% respectively, but no reductions were recorded in testosterone-supplemented rats. Other cell types present in stage VII were unaffected by treatment in all groups. These results suggest that cisplatin retards spermatogenesis by inhibiting testosterone production, since concomitant testosterone therapy prevents cellular damage. Although data supporting this conclusion are clear-cut, their interpretation may not be so, especially in view of some reports suggesting minor germ cell loss at stage VII upon testosterone withdrawal. Probably of equal or more importance is the direct action of cisplatin on dividing germ cells through DNA binding.

Response of the seminiferous epithelium of the rat testis to withdrawal of androgen: evidence for direct effect upon intercellular spaces associated with Sertoli cell junctional complexes

The morphological response of the Sertoli cells to partial or complete withdrawal of testosterone was studied in adult rats following hypophysectomy or administration of ethane dimethanesulphonate (EDS), a toxicant known to destroy selectively the Leydig cells of the testis. To assess the role of germ cells in effecting changes to Sertoli cells following withdrawal of testosterone, germ cell-deficient rats with Sertoli-cell-only testes (SCO) were treated with EDS to remove the source of testosterone. At 6 days after hypophysectomy or 4, 6 and 8 days after EDS treatment, stage VII and VIII seminiferous tubules showed degenerating germ cells and numerous basally-located vacuoles approximately 1-15 microns in diameter. Ultrastructural analysis indicated that most of the vacuoles were multiple focal dilations of the intercellular space associated with Sertoli cell junctional complexes. In SCO rats, treatment with EDS resulted in a significant (P < 0.05) increase in the formation of many vacuoles particularly in the base but also in the trunk of the Sertoli cells and again electron microscopic analysis showed multiple, localized expansions of the intercellular space associated with Sertoli cell junctional complexes. The appearance of intercellular spaces in SCO testes following androgen withdrawal cannot be attributed to shrinkage of degenerating germ cells since the seminiferous tubules did not contain germ cells. It is concluded that withdrawal of androgen induces early morphological alterations of the Sertoli cell junctional complexes in which the sites of membrane fusions representing tight junctions remain intact whereas the intercellular spaces exhibit major focal dilations.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative roles of testosterone and the germ cell complement in determining stage-dependent changes in protein secretion by isolated rat seminiferous tubules

This study has compared the effect of withdrawal of testosterone (+/- replacement) with that of selective depletion of pachytene spermatocytes (PS) or round/elongating spermatids (RS), or both PS and RS, on the level of overall protein secretion by seminiferous tubules (ST) isolated at particular stage-groups of the spermatogenic cycle. Testosterone withdrawal was induced by destroying the Leydig cells with a single injection of ethane-dimethane sulphonate (EDS), with or without concomitant replacement of testosterone by injection; ST at stages II-V, VI-VIII or IX-XII were then isolated from control and treated rats at 4 days after treatment. Methoxyacetic acid (MAA) was administered, in either one or two doses, to selectively destroy 80-100% of pachytene and later spermatocytes; ST at stages I-V, VI-VIII or IX-XIV were then isolated at specific times after treatment such that ST were depleted selectively of either PS, RS or PS+RS. Isolated ST (5 cm) were then cultured for 22 h at 34 degrees C with 35S-methionine and its incorporation into secreted proteins then quantified. Based on the incorporation of 35S-methionine, ST at stages VI-VIII showed a significantly higher level of protein secretion than did ST at earlier or later stages. This difference was abolished following testosterone withdrawal but was maintained by testosterone replacement. The normal increase in protein secretion by ST at stages VI-VIII was also prevented if either PS or RS were depleted, whereas depletion of either PS or RS alone had no significant effect on protein secretion by ST at stages I-V, and only the depletion of RS significantly reduced protein secretion by ST at stages IX-XIV. Depletion of both PS+RS reduced protein secretion significantly by ST at all stages. In contrast to the data for total protein secretion, the levels of sulphated glycoprotein (SGP)-1 and SGP-2 secreted by ST at stages VI-VIII showed that these two Sertoli cell proteins were unaffected by germ cell depletion except after co-depletion of PS+RS when secretion of SGP-1 was halved.(ABSTRACT TRUNCATED AT 400 WORDS)