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PubMed2005

Effects of glial cell line-derived neurotrophic factor on isolated developing mouse Sertoli cells in vitro.

Cell proliferation is a key factor in sex determination where a size increase relative to the XX gonad is one of the first signs of testis differentiation. Moreover, proliferation of Sertoli cells during development is important in building up the stock of supporting cells necessary for subsequent successful fertility. Because proliferation is such an essential part of testis development, the hypothesis under long-term investigation is that it is under fail-safe control by multiple alternative growth factors. This study was undertaken to investigate the role of glial cell-derived neurotrophic factor (GDNF) on developing mouse Sertoli cells in vitro. Sertoli cells, isolated from mouse embryos at three stages of testis development, were maintained for 2-7 days in vitro (div) in the presence or absence of GDNF at 1, 10 and 100 ng mL(-1). Overall the presence of extracellular matrix gel had little effect on proliferative activity, but encouraged expression of the epithelial phenotype. A statistically significant difference in proliferation, assessed by immunocytochemical staining for proliferating cell nuclear antigen, was seen with GDNF at embryonic day (E)12.5 after 2 div (at both 10 and 100 ng mL(-1), P < 0.001) and 7 div (at both 10 and 100 ng mL(-1), P < 0.05); at E13.5 after 3 div (at both 10 and 100 ng mL(-1), P < 0.05) and at E14.5 after 7 div (100 ng mL(-1), P < 0.01), compared with controls cultured without growth factor. In conclusion, GDNF stimulates mitosis throughout this critical developmental window. The in vitro approach used here is a useful adjunct to the knockout mouse model and has been applied to show that GDNF exerts a proliferative effect on developing mouse Sertoli cells.

Animals↗
PubMed2006

Pathways of endocrine disruption during male sexual differentiation and masculinization.

After testis formation, further development of a male phenotype (masculinization) is driven by three hormones from the foetal testis: anti-Müllerian hormone, insulin-like factor 3, and testosterone. These hormones divert the development of reproductive and other organs from female to male and also play a role in testis development. The hormone dependence of masculinization renders this process inherently susceptible to disruption by factors that interfere with hormone production, bioavailability, metabolism, or action. This susceptibility is illustrated by the high prevalence of congenital masculinization disorders (cryptorchidism, hypospadias) and disorders in young adult men (low sperm counts, testis cancer), which may also stem from maldevelopment (dysgenesis) of the foetal testis. Testicular dysgenesis occurring in humans, or which is induced in animal models by foetal exposure to certain phthalates, is associated with impaired hormone production by the foetal testis. There is currently no definitive evidence that exposure of humans to environmental chemicals can induce testicular dysgenesis and/or impair masculinization, though pathways via which this could potentially occur are established.

Animals↗
PubMed1991

Transgenic mice demonstrate a testis-specific promoter for angiotensin-converting enzyme.

There are two isozymes of angiotensin-converting enzyme (ACE), one produced by somatic tissues and a smaller protein synthesized by developing spermatozoa (testis ACE). To investigate the molecular control of testis ACE, we generated mice transgenic for a construct containing a putative testis-specific ACE promoter linked to the Escherichia coli reporter gene encoding beta-galactosidase. The transgenic mice express beta-galactosidase protein and RNA only within the testis. Histochemical analysis of the transgenic mice shows co-localization of beta-galactosidase protein and endogenous ACE within elongating spermatozoa. These studies demonstrate that transcription of testis ACE is controlled by a strong intragenic testis-specific promoter that is contained within a 698-base pair fragment immediately upstream from the transcription start site of testis ACE. Characterization of the testis ACE promoter may provide insights into the molecular mechanisms controlling cell stage-specific gene expression in the male germ line.

Animals↗
PubMed2002

[Isolation and identification of spermatids from mouse testis].

OBJECTIVES: To develop a simple and effective method by which spermatids can be isolated from mouse testis. METHODS: Combination of enzymatic digestion was used to prepare suspension of spermatogenic cells from adult mouse testis, and then a modified discontinuous Percoll gradient (15%, 22%, 30%, 40%, 50%, 60%) centrifugation method was introduced to isolate spermatids from the cellular suspension. The content of spermatids in each isolated fraction by Percoll method was determined by morphology (Wright-Giemsa staining) and flow cytometry analysis, and the viability of spermatogenic cells was assessed using Eosin Y exclusion test. RESULTS: More than 97% of the testicular cells remained their viability after enzymatic digestion. After Percoll centrifuged, six fractions were formed. In each isolated fraction, the 22% fraction contained mostly spermatids(mean 86.7%) and cell viability was more than 85.5%. While in the 30% fraction, immature spermatogenic cells were present, and more than 92% of the cells remained their viability. CONCLUSIONS: A large of relatively purified spermatids can be isolated from mouse testis by enzymatic digestion combined discontinuous Percoll gradient centrifugation method.

Animals↗
PubMed1999

Specific expression of the mRNA for 25 kDA heat-shock protein in the spermatocytes of mouse seminiferous tubules.

The 25 kDa heat-shock protein (Hsp25) is a member of the family of small heat-shock proteins. We investigated the expression and cellular localization of Hsp25 mRNA in the testis of adult and developing mice using Northern blotting and in situ hybridization techniques. In the early postnatal days, i.e., before the onset of spermatogenesis, no Hsp25 mRNA was detected in the testis. At around 10 days postpartum, Hsp25 mRNA began to be expressed in the testis in coincidence with the onset of the first wave of spermatogenesis and increased in amount progressively toward adulthood. Throughout the testis development, the signal for Hsp25 mRNA was localized exclusively to germ cells and was not detected in Sertoli or interstitial cells. The testis of W/Wv mutant mice, which lack the germ cell line, exhibited no Hsp25 mRNA expression. In the testis of normal adult mice, the abundance of Hsp25 mRNA differed among the seminiferous tubules in different stages of spermatogenesis. The most intense signal for Hsp25 mRNA was localized to the spermatocytes at leptotene, zygotene and early pachytene phases, which are present in the tubules of stages I-III and IX-XII. The signal decreased in intensity in the late pachytene and diplotene spermatocytes and was not detected in spermatids. Spermatogonia were also devoid of the signal. These results suggested that Hsp25 plays some specific role in the meiotic prophase of the testicular germ cell.

Animals↗
PubMed1989

Quantitation of testicular and somatic cytochromes c in testis and somatic tissues from developing rats.

By combining chromatographic and spectral procedures, simple and quantitative assays for somatic cytochrome c (cyt cs) and testicular cytochrome c (cyt ct) in crude animal tissue extracts were developed. Using this assay procedure, limited developmental studies of cyt ct and cs were performed with tissue extracts of 27-, 58-, and 85-day-old rats. Specific contents of cyt cs in somatic tissues (i.e., micrograms of cyt c/g of tissue) of these three age groups did not show significant variations. However, the amounts of both cyt ct and cs in testis were markedly increased as the rats approached maturity. Increasing cyt ct/cyt cs ratios as the rat developed to maturity suggest that expression of cyt ct is preferentially required for specific function of testis. Application of both molecular biological techniques and this assay (for holo-cyt ct) should be useful to study the overall regulation of the expression of cyt ct in testis.

Aging↗
PubMed2005

Developmentally distinct in vivo effects of FSH on proliferation and apoptosis during testis maturation.

The critical influence of follicle stimulating hormone (FSH) on male fertility relates both to its impact on Sertoli cell proliferation in perinatal life and to its influence on the synthesis of Sertoli cell-derived products essential for germ cell survival and function in the developing adult testis. The nature and timing of this shift of germ cells to their reliance on specific Sertoli cell-derived products are not defined. Based on existing data, it is apparent that the dominant function of FSH shifts between 9 and 18 day postpartum (dpp) during the first wave of spermatogenesis from driving Sertoli cell proliferation to support germ cells. To enable comprehensive analysis of the impact of acute in vivo FSH suppression on Sertoli and germ cell development, FSH was selectively suppressed in Sprague-Dawley rats by passive immunisation for 2 days and/or 4 days prior to testis collection at 3, 9 and 18 dpp. The 3 dpp samples displayed no measurable changes, while 4 days of FSH suppression decreased Sertoli cell proliferation and numbers in 9 dpp, but not 18 dpp, animals. In contrast, germ cell numbers were unaffected at 9 dpp but decreased at 18 dpp following FSH suppression, with a corresponding increase in germ cell apoptosis measured at 18 dpp. Sixty transcripts were measured as changed at 18 dpp in response to 4 days of FSH suppression, as assessed using Affymetrix microarrays. Some of these are known as Sertoli cell-derived FSH-responsive genes (e.g. StAR, cathepsin L, insulin-like growth factor binding protein-3), while others encode proteins involved in cell cycle and survival regulation (e.g. cyclin D1, scavenger receptor class B 1). These data demonstrate that FSH differentially affects Sertoli and germ cells in an age-dependent manner in vivo, promoting Sertoli cell mitosis at day 9, and supporting germ cell viability at day 18. This model has enabled identification of candidate genes that contribute to the FSH-mediated pathway by which Sertoli cells support germ cells.

Animals↗
PubMed2005

Contribution to the origin and development of the appendices of the testis and epididymis in humans.

Hydatids, as appendices of testis or epididymis, were discovered by Morgagni in 1703 and 1705 and published by him in 1761. Hydatids are considered to be remnants of the cranial part of the Mullerian duct (MD), Wolffian duct (WD), or mesonephric tubules. They are localized as sessile or pedunculated appendices at the cranial pole of testis and at the head of epididymis, or at analogous organs in women. The clinical relevance is known: acute scrotum with torsion of appendices, or metaplasia. However, little is known about the embryological development of hydatids. Therefore, we studied the origin and development of appendix testis (AT) and appendix epididymidis (AE) in human embryos from stage 14 (Carnegie Collection), 6.5 mm GL, 32 days, to fetuses of 170 mm, 17th week. Light and scanning-electron microscopy as well as plastic reconstructions from serial sections of the cranial parts of MD and WD reveal that hydatids already form during regression or transformation of the ducts. At stage 18, 15-16 mm GL, 44 days, the cranial parts of MD and WD exhibit morphological features that give a preview on the definite form and position of later appendices. In fetuses from 45 mm GL, ninth week onward, we found anlagen of pedunculated hydatids (AE) deriving from the ampullated cranial end of the WD, which in many cases opened into the coelomic cavity. The unpedunculated AT derived from the persisting funnel region of the MD. The development of duct-independent, accessory appendices was observed. We paid special attention to a pedunculated hydatid in a fetus of 120 mm, 14th week, and the cranial regressing WD. A classification of hydatids is presented. Photographs and histological sections of (sessile) appendices testis (AT), and (pedunculated) appendices epididymidis (AE) with torsion of stalks exhibit the final forms and positions of hydatids in adult.

Animals↗
PubMedDate not supplied

Development of the human fetal testis.

We describe the histological features of the fetal testis, utilizing 68 fetuses ranging in gestational age from 10 to 41 weeks. During fetal life, the tunica albuginea progressively increases in thickness, and between 29 and 32 weeks it develops two layers. Beyond 25 to 28 weeks, septa are invariably present. Tubules begin as straight structures and become maximally coiled by 30 weeks. Tubular diameter reaches its maximum by 16 weeks and remains constant throughout the rest of gestation. Germ cell and Sertoli cell numbers per tubular diameter have a wide range, but the median number for each cell type remains constant after 13 to 16 weeks. Leydig cells are most numerous between 17 and 19 weeks and decline thereafter. They are infrequent but still present at term. Interstitial lipochrome pigment accumulates during the latter half of gestation and may represent breakdown products from Leydig cell degeneration.

Embryonic and Fetal Development↗
PubMed1975

Androgen binding protein as a biochemical marker of formation of the blood-testis barrier.

Androgen binding protein (ABP) was measured during postnatal development in normal and irradiated rats to determine whether development of a blood-testis barrier and formation of a continuous lumen from testis to epididymis is correlated with entry of ABP into the caput epididymis. ABP is found in normal testis as early as 14 days postnatally (0.2 pmol/mg), at which time no blood-testis barrier is observed by the peroxidase perfusion technique. Previous findings have shown a close correlation of blood-testis barrier development and lumen formation. Indeed, ABP is not detectable in the epididymis until 18-20 days of age (1.0 pmol/mg) at which time blood-testis barrier formation and lumen development is complete. Whole body irradiation (125 rads) of pregnant rats at 19-20 days of gestation produces male offspring with seminiferous tubules remarkably free of germinal epithelium and containing essentially only Sertoli cells. These Sertoli cell-enriched (SCE) testes produce normal amounts of ABP between 14 and 21 days postnatally. However, between 21 and 30 days of age the specific activity of ABP is significantly higher in the SCE tests (2.8 pmol/mg protein) than in normal testis (0.5 pmol/mg protein). In the SCE testis neither blood-testis barrier development nor lumen formation are complete until 30 days of age, at which time ABP is first detectable in epididymis of the irradiated rat. Thereafter there is a gradual decline of ABP in the SCE testis-and a dramatic increase in the epididymis. NIH-FSH-S-10 (200 mug/rat) injected SC into 14-day-old normal rats stimulated ABP in the testis from control levels of 0.15 pmol/mg to 1.46 pmol/mg within 4 h after injection. However, no ABP was detectable in the epididymis of either the control or the FSH-stimulated rats. These findings suggest that entry of ABP into caput epididymis is an index of blood-testis barrier formation and lumen development.

Androgens↗
PubMed1981

The influence of neonatal orchiopexy upon the testis in persistent Müllerian duct syndrome.

We report on a patient with persistent müllerian duct syndrome and normal external genitalia who had embryonal cancer of the testis 16 years after neonatal bilateral orchiopexy. In previous cases the testes of these patients have not been considered predisposed to form tumors. However, the occurrence of a testis tumor has been reported in 8 patients with this syndrome. The specific factors resulting in tumor formation in such patients are uncertain. Until they are clarified we suggest that these patients should be observed carefully for the possible development of testis tumor.

Adolescent↗
PubMed1987

Isolation and partial characterization of basic fibroblast growth factor from bovine testis.

A basic fibroblast growth factor (FGF) has been purified to homogeneity from bovine testis, using ammonium sulfate precipitation of the crude extract followed by three chromatographic steps, involving cation-exchange, heparin-Sepharose, and reversed-phase HPLC. Gas-phase sequence analysis showed the amino-terminal amino acid sequence of the isolated polypeptide as His-Phe-Lys-Asp-Pro-Lys-Arg-Leu-Tyr-, which is identical to the amino-terminal of the (16-146) fragment of basic FGF previously characterized from corpus luteum, adrenal, and kidney. The purified FGF was shown to have the same biological activity as that of basic FGF (1-146). This finding suggests that basic FGF is present in testis and may act as a local regulator of testicular function. In addition, testicular FGF might play an important role in spermatogenesis and/or the development of testis.

Amino Acid Sequence↗
PubMed1993

Testicular cancer.

Despite the overall cure rate now in excess of 90%, innovation in management of germ cell tumors continues. The report that 80% of patients with extragonadal germ cell tumors have either carcinoma in situ or atrophic tubules as evidence of tumor rejection emphasizes the need to investigate the testis in patients with undiagnosed primary cancer because even today treatment delay is worsening prognosis. The evidence that testicular atrophy is a precursor of malignancy may explain why testis cancer has increased while normal sperm count has fallen over the past 50 years and why there is an association between exposure during service in Vietnam to agents that damage spermatogenesis and development of testis cancer. The improved prognostication from analysis of large databases and salvage with high-dose chemotherapy and bone marrow rescue are giving confidence to explore new innovations, eg, carboplatin instead of cisplatin. In addition, as the database on patients with stage I disease on surveillance enlarges, so does interest in adjuvant chemotherapy, encouraging the search for better markers to predict poor response. Linkage between overproduction of the tumor marker lactate dehydrogenase-1 and the increased copy number of the isochrome 12p in the tumor may be of use in this respect. Reports that germ cell tumor patients exposed to etoposide, eg, leukemic, lung, and ovarian cancer patients, can develop an acute myeloid leukemia with a marker on chromosome 11 are tempering enthusiasm for its use in adjuvant therapy. However, the observation that radiotherapy or chemotherapy may reduce second testis tumor incidence more effectively than surgery does encourages more detailed exploration of the results of adjuvant treatment.

Dysgerminoma↗
PubMed2004

Molecular and genetic regulation of testis descent and external genitalia development.

Testicular descent as a prerequisite for the production of mature spermatozoa and normal external genitalia morphogenesis, and therefore facilitating copulation and internal fertilization, are essential developmental steps in reproduction of vertebrate species. Cryptorchidism, the failure of testis descent, and feminization of external genitalia in the male, usually in the form of hypospadias, in which the opening of the urethra occurs along the ventral aspect of the penis, are the most frequent pediatric complications. Thus, elucidating the molecular mechanisms involved in the regulation of testis descent and the formation of external genitalia merits a special focus. Natural and transgenic rodent models have demonstrated both morphogenic processes to be under the control of a plethora of genetic factors with complex time-, space-, and dose-restricted expression pattern. The review elucidates the molecular mechanisms involved in the regulation of testis descent and the formation of external genitalia and, wherever possible, assesses the differences between these rodent animal models and other mammalian species, including human.

Androgens↗
PubMed1994

Suppressive effect of fetal testes on development of fetal ovaries transplanted into adult males in the rat.

The age-related testicular effect on the ovarian primordia was studied by combined transplantation of fetal testes and ovaries in adult male hosts. First, ovarian primordia of 14-day fetal rats were transplanted into a renal subcapsular position of castrated or intact adult male rats. In both the castrated and the intact hosts, most of the ovarian transplants developed normally with only 3 of them having in part seminiferous tubule-like structures in addition to normal ovarian structure. Second, a 14-day ovary was combined with a fetal testis the age of which varied from 13- to 18-day, and the combination was transplanted. In the combination of a 14-day ovary and a 13-day testis, the results varied in such a way that the ovary or the testis alone developed or otherwise, both gonads developed well. In union with 15- to 18-day testes, the ovaries did not develop, although the testes developed well. These results suggest that the 14-day ovarian primordia have a slight reactiveness to androgens of host rats and that the 13-day fetal testes begin to inhibit the development of the 14-day ovaries co-transplanted with them.

Animals↗
PubMed2006

The identification and characterization of a testis-specific cDNA during spermatogenesis.

Using bioinformatics and experimental validation, we obtained a cDNA (named srsf) which was exclusively expressed in the mouse testes. RT-PCR analysis showed that srsf mRNA was not expressed in the gonad during the sex determination period or during embryogenesis. In developing mouse testis, srsf expression was first detected on post-natal day 10, reached its highest level on day 23, and then reduced to and remained at a moderate level throughout adulthood. In situ hybridization analysis demonstrated that srsf mRNA was expressed in pachytene spermatocytes and round spermatids in the testes. The predicted protein contains one RNA-binding domain (RBD) and a serine-arginine rich domain (RS), which are characterized by some splicing factors of SR family members. These findings indicate that srsf may play a role during spermatogenesis.

Amino Acid Sequence↗
PubMed1999

Retinoic acid receptors and retinoid X receptors in the rat testis during fetal and postnatal development: immunolocalization and implication in the control of the number of gonocytes.

Retinoids have pleiotropic effects on embryonic development and are essential for spermatogenesis in the adult, where they act via nuclear retinoid receptors: retinoic acid receptors (RARs) and retinoid X receptors (RXRs). We used immunohistochemistry to examine the cellular localization of RARs and RXRs in the rat testis from Day 13.5 postconception (13.5 dpc) until Day 8 postpartum (8 dpp), and these findings were compared with those for immature and adult testes. RARalpha and RARbeta were detected in the interstitial tissue from 14.5 dpc, with intense staining in the gonocytes from 20. 5 dpc to 8 dpp. The nuclei of all cell types stained faintly for RARgamma from 8 dpp. Immunoreactivity for RXRalpha was intense in the gonocytes from 13.5 dpc and in the Leydig cells from 16.5 dpc, and persisted throughout the period studied. RXRbeta was always detected in the Leydig cells and during a short neonatal period in the gonocytes. RXRgamma gave a faint reaction in the nuclei of all cell types from 20.5 dpc. Unexpectedly, immunostaining for all the receptors tested, except RARgamma and RXRgamma, was detected in the cytoplasmic compartment of the cells of fetal and neonatal testes, while it was found in the nuclei in immature and adult testes. In cultures of dispersed testicular cells from 3 dpp pups, retinoic acid had a dose-dependent deleterious effect on the survival of the gonocytes and, to a lesser extent, of the somatic cells. These results suggest that retinoids act on the testicular development, especially on germ cells, via RARs and/or RXRs.

Animals↗
PubMed2005

Ontogenetic profile and thyroid hormone regulation of type-1 and type-8 glucose transporters in rat Sertoli cells.

The glucose transporters (GLUTs) gene encode glycoproteins responsible for facilitating transfer of glucose across plasma membrane. In testis, different members of this family are present. In particular the main GLUT mRNA expression within the adult testis is the type 8, while type 1 is more expressed in prepubertal testis. Thyroid hormone, which receptors and function have been characterized in the testis, plays a crucial role in the cellular energetic metabolism. In fact, in the immature Sertoli cells, GLUT1 is up regulated by l-triiodothyronine (T(3)). The aim of this paper is to investigate the expression profile of GLUT1 and GLUT8 in the testis during development and in adulthood and analyse the role of T(3) on their expression. To analyse the expression of GLUT8 and GLUT1 we performed Northern blot and RT-PCR experiments in the whole testis and in Sertoli cells from rats of different ages. Treatments in vivo and in vitro with T(3) were used to study the effect of thyroid hormones on GLUT1 and GLUT8 expression. The activity of the rat GLUT1 promoter and its regulation by T(3) was studied with transient transfections in gonadal and non-gonadal cell lines and in primary Sertoli cell cultures. GLUT8 is expressed at a low level in the prepubertal testis and Sertoli cells and does not appear to be under T(3) control. GLUT1 is the predominant form in immature Sertoli cells. The effect of T(3) on its mRNA accumulation was quantified and confirmed by RT-PCR (control: 0.65 +/- 0.17; T(3): 1.23 +/- 0.04, arbitrary units, p < 0.05). However, transfection experiments showed that T(3) does not directly regulate GLUT1 promoter in any cell line tested. This is confirmed by the evidence that, upon extensive analysis, the rat GLUT1 promoter and the first intron sequence do not shows any thyroid responsive elements. Our data demonstrate that GLUT1 and GLUT8 are both expressed in prepubertal testis, but only GLUT1 is regulated by T(3). In addition, we found that the effect of T(3) cannot be attributed to its action on GLUT1 promoter.

Animals↗