Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “testis development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1998

Stem cells in the testis.

The origin and development of the spermatogenic cell lineage is reviewed, as well as spermatogonial kinetics in adult nonprimate mammals in relation to the cycle of the seminiferous epithelium, the emphasis being on spermatogonial stem cells. A hypothesis is presented for the transition from foetal germ cells, gonocytes, to adult type spermatogonia at the start of spermatogenesis. An overview is given of the present knowledge on the proliferation and differentiation of undifferentiated spermatogonia (spermatogonial stem cells and their direct descendants) and the regulation of these processes. It is concluded that the differentiation of the undifferentiated into differentiating type spermatogonia is a rather vulnerable moment during spermatogenesis and the models for studying this are described. Research into the molecular basis of the regulation of spermatogonial proliferation, differentiation and apoptosis is at its infancy and the first results are reviewed. An exciting new research tool is the spermatogonial stem cell transplantation technique which is described. Finally, reviewing the nature of human germ cell tumours it is concluded that at present there are no animal or in vitro models to study these tumours experimentally.

Animals↗
PubMed1994

Type VI collagen in the rat testis: monoclonal antibody, isolation, and localization during development.

To investigate the components of the seminiferous tubule extracellular matrix (ST-ECM), monoclonal antibodies were raised against ST-ECM. One of these (15B6) recognized the nonreduced form of type VI collagen. With this antibody as a probe, type VI collagen was isolated from an SDS-urea extract of ST-ECM. It took a tetrameric form, and upon reduction dissociated into a major 140-kDa band and two bands at 190 and 210 kDa. Developmental changes in the distribution of type VI collagen were investigated by immunofluorescence microscopy. In 16-day rat embryos when myoid cells began to differentiate, type VI, collagen was seen in the urogenital mesentery, and it had begun to surround the gonad and, in some embryos, the seminiferous cords. In newborn rats, it was found throughout the extracellular spaces between the cords, being localized in the interstitium. In adults, however, it was confined to two parallel lines around the seminiferous tubules and to filamentous structures in the adventitia of vascular systems. Immunoelectron microscopy showed that this collagen was distributed in the interstitium independently from collagenous fibrils, but was excluded from the basal lamina of Sertoli cells. These observations indicate that type VI collagen is a major component of the ST-ECM and that it may be important in the organization of the matrix and in the differentiation of peritubular cells.

Aging↗
PubMed1998

Interferons and interferon-induced antiviral proteins in the testis.

Despite the dramatic development of sexually transmissible diseases, the antiviral capabilities of testicular cells have not yet been explored. Interferons (IFNs) are proteins playing a key role in the antiviral defense system, their activity being mediated by several IFN-induced proteins. In the present study, we have investigated both the expression of IFN and of the three main IFN-induced proteins by isolated testicular cells. The highest responders to a viral stimulation in terms of IFN production are the Leydig and the Sertoli cells, followed by peritubular cells and testicular macrophages, while germ cells are devoid or virtually devoid of IFN and IFN-induced protein expression. Sertoli cells constitutively expressed the three IFN-induced proteins tested, and their levels were greatly increased after exposure to Sendai virus. Peritubular cells were also able to markedly express these three proteins after viral exposure. In conclusion, we hypothesize that, for a virus coming from the blood, the first testicular line of defence is ensured by Leydig cells and testicular macrophages, the second line being ensured by the myoid cells, lining the seminiferous tubules, and by Sertoli cells. These two barriers are probably fundamental in protecting both androgen production and spermatogenesis.

Animals↗
PubMed1989

Maternally-mediated neonatal lithium-cesium interaction in the mouse.

The effect of maternal exposure to LiCl, CsCl or both salts in the weaning and developing offspring mice was studied on selected organ weights, hepatic and cardiac dehydrogenase enzymes. The concentration of alkali metal used in maternal drinking fluid during pregnancy and breast-feeding did not produce taste aversion and therefore approximate equal consumption was assured. Maternal exposure to either alkali metal reduced brain and testis weights of the developing offspring mice compared to controls. This suggests a delayed toxic effect on the CNS and endocrine organs. Coadministration of both salts negated this effect. The maternal neonatal Li-mediated increases of weanling spleen weight and the reduction of testis weight of developing offspring mice by Li or Cs were not evident when both alkali metals were given in combination. The combined maternal exposure to both Li and Cs salts also negated the induction of offspring mouse liver alcohol dehydrogenase produced by either alkali metal alone. Likewise, the induction of developing mouse heart lactate dehydrogenase isoenzyme (LDH5) by maternal exposure to LiCl was no more apparent by the combined Li and Cs treatment. These data suggest a Li+-Cs+ interaction in the offspring mouse due to maternal exposure to these alkali metals during pregnancy and breast-feeding periods. The results also suggest that both alkali metals most probably have been delivered to the suckling pups and some of their toxic effect was retarded.

Alcohol Dehydrogenase↗
PubMed2000

SRY protein is expressed in ovotestis and streak gonads from human sex-reversal.

In mammals, a master gene located on the Y chromosome, the testis-determining gene SRY, controls sex determination. SRY protein is expressed in the genital ridge before testis determination, and in the testis it is expressed in Sertoli and germ cells. Completely sex-reversed patients are classified as either 46,XX males or 46,XY females. SRY mutations have been described in only 15% of patients with 46,XY complete or partial gonadal dysgenesis. However, although incomplete or partial sex-reversal affects 46,XX true hermaphrodites, 46,XY gonadal dysgenesis, and 46,XX/46,XY mosaicism, only 15% of the 46,XX true hermaphrodites analyzed have the SRY gene. Here, we demonstrate that the SRY protein is expressed in the tubules of streak gonads and rete testis, indicating that the SRY protein is normally expressed early during testis determination. Based on these results, we propose that some factors downstream from SRY may be mutated in these 46,XY sex-reversal patients. We have also analyzed SRY protein expression in the ovotestis from 46,XX true hermaphrodites and 46,XX/46,XY mosaicism, demonstrating SRY protein expression in both testicular and ovarian portions in these patients. This suggests that the SRY protein does not inhibit ovary development. These results confirm that other factors are needed for complete testis development, in particular, those downstream of the SRY protein.

DNA-Binding Proteins↗
PubMed2003

GLIS3, a novel member of the GLIS subfamily of Krüppel-like zinc finger proteins with repressor and activation functions.

In this study, we describe the identification and characterization of a novel transcription factor GLI-similar 3 (GLIS3). GLIS3 is an 83.8 kDa nuclear protein containing five C2H2-type Krüppel-like zinc finger motifs that exhibit 93% identity with those of GLIS1, however, little homology exists outside their zinc finger domains. GLIS3 can function as a repressor and activator of transcription. Deletion mutant analysis determined that the N- and C-termini are required for optimal transcriptional activity. GLIS3 binds to the GLI-RE consensus sequence and is able to enhance GLI-RE-dependent transcription. GLIS3(DeltaC496), a dominant-negative mutant, inhibits transcriptional activation by GLIS3 and GLI1. Whole mount in situ hybridization on mouse embryos from stage E6.5 through E14.5 demonstrated that GLIS3 is expressed in specific regions in developing kidney and testis and in a highly dynamic pattern during neurulation. From E11.5 through E12.5 GLIS3 was strongly expressed in the interdigital regions, which are fated to undergo apoptosis. The temporal and spatial pattern of GLIS3 expression observed during embryonic development suggests that it may play a critical role in the regulation of a variety of cellular processes during development. Both the repressor and activation functions of GLIS3 may be involved in this control.

Amino Acid Sequence↗
PubMed1997

Tissue-specific expression of murine Nkx3.1 in the male urogenital system.

The molecular mechanisms involved in growth and morphogenesis of the mammalian urogenital system are largely undefined. In this study, we describe the cloning and characterization of a novel murine homeobox gene, Nkx3.1, which is expressed in the male urogenital system during late embryogenesis and adulthood. We show that Nkx3.1 encodes a 38 kDa homeoprotein that has DNA binding properties similar to those of other Nkx family members. By RNAse protection analysis, we demonstrate that Nkx3.1 is expressed in late-gestation embryos and adults by tissues of the male urogenital system, including the testis, seminal vesicle, and the prostate. In adult males, expression of Nkx3.1 in the prostate increases during sexual maturation, and is significantly reduced following castration, suggesting that androgens are required for maintenance of Nkx3.1 expression. In situ hybridization analysis of mid- and late-gestation male embryos shows that Nkx3.1 is expressed in the developing urogenital sinus, testis, and prostatic buds. In addition to its expression in the urogenital system, we also find that Nkx3.1 is expressed in the dorsal aorta and kidney. These results implicate Nkx3.1 in the growth and development of the prostate and/or other tissues of the male urogenital system, and suggest that Nkx3.1 may play a role in sexually dimorphic as well as non-sexually dimorphic organogenesis.

Amino Acid Sequence↗
PubMed2003

AMH induces mesonephric cell migration in XX gonads.

Migration of mesonephric cells into XY gonads is a critical early event in testis cord formation. Based on the fact that anti-Müllerian hormone (AMH) can induce testis cord formation in XX gonads, we investigated whether AMH plays a role in the induction of cell migration. Addition of recombinant AMH induced mesonephric migration into XX gonads in culture. AMH-treated XX gonads displayed increased vascular development and altered morphology of the coelomic epithelium, both features of normal testis differentiation. AMH did not induce markers of Sertoli or Leydig cell differentiation. We examined early testis development in Amh-deficient mice, but found no abnormalities, suggesting that any function AMH may have in vivo is redundant. Other transforming growth factor (TGF-beta) family proteins, bone morphogenetic proteins (BMP2 and BMP4) show similar inductive effects on XX gonads in culture. Although neither BMP2 nor BMP4 is expressed in embryonic XY gonads, our findings suggest that a TGF-beta signalling pathway endogenous to the XY gonad may be involved in regulation of mesonephric cell migration. The factors involved in this process remain to be identified.

Animals↗
PubMed1988

Cell-autonomous action of the testis-determining gene: Sertoli cells are exclusively XY in XX----XY chimaeric mouse testes.

The distribution of XX and XY cells in XX----XY chimaeric mouse testes was analysed by enzyme marker analysis of separated testicular tissues and by in situ DNA marker analysis of air-dried testicular cells and testis sections. XX cells contributed to the Leydig cells, the peritubular cells and the vascularized connective tissue of the tunica albuginea. The Sertoli cells, on the other hand, appeared to be exclusively XY. These results indicate that during the development of the testis, Sertoli cell differentiation is triggered by cell-autonomous activity of the Y chromosomal testis-determining gene Tdy. Subsequent steps in testis differentiation may be a consequence of Sertoli cell activity.

Animals↗
PubMed2004

Environmental anti-androgens and male reproductive health: focus on phthalates and testicular dysgenesis syndrome.

The amount of research into endocrine disruption has exploded over the past decade and a re-evaluation of the state of research in this area is timely. There are debates about whether human male reproductive health is really declining and whether endocrine disrupting chemicals play any role in the perceived decline. Most data currently conclude that there are wide geographical variations in semen quality and in the incidence of testicular cancer, cryptorchidism and hypospadias. This review aims to give a brief overview of the issues surrounding the perceived decline in human male reproductive health and the importance of the hormonal environment for the development of the testis and reproductive tract. The consequences for the male reproductive tract of abnormal androgen levels or action are discussed with reference to environmental anti-androgenic compounds. The in vivo data on several anti-androgenic compounds that have been administered to pregnant rodents during the period of male reproductive tract development are assessed with attention to the effects on the male offspring. Finally, the data on in utero phthalate administration are discussed in detail to illustrate the similarities between the effects of some phthalate esters and the human male reproductive tract disorders which comprise testicular dysgenesis syndrome (TDS).

Androgen Antagonists↗
PubMed1999

Androgenic gland hormone is a sex-reversing factor but cannot be a sex-determining factor in the female crustacean isopods Armadillidium vulgare.

Sex reversal of female isopods, Armadillidium vulgare, has been induced by implantation of the androgenic gland (AG) into individuals after the initiation of morphological sex differentiation. The focus of the present study is to examine whether female gonads are reversed by the androgenic gland hormone (AGH) during the sexually undifferentiated period through postembryonic development in A. vulgare. Instead of injections of AGH, three AGs were implanted into each genetic female at various developmental stages to induce sex reversal. Before implantation fresh AGs were treated with ethanol to stop AGH synthesis, but then still contained AGH. These AGs have been referred to as ethanol-treated AGs (t-AGs). Development of a testis was used as an indicator of gonadal sex reversal. The gonads of genetic females were transformed into testes by implantations of t-AGs during the sex differentiation period. However, when genetic females received implants at sexually undifferentiated stages, development of their gonads was not reversed in the male direction. These results suggest that after the onset of gonadal sex differentiation, AGH is a sex-reversing factor that can turn a female gonad into a male gonad. AGH cannot be a sex-determining factor in female A. vulgare, as undifferentiated gonads of genetic females are not sex reversed by the hormone.

Aging↗
PubMed1975

LH-hCG receptors and testosterone content during differentiation of the testis in the rabbit embryo.

The development of gonadotropin receptors for LH and hCG in the fetal rabbit testis from 17-29 days of gestation was followed by quantitative binding studies with [125I]iodohCG and compared with gonadal testosterone content and the histological differentiation of the fetal Leydig cells. The concentrations of gonadotropin receptors and testosterone in the fetal testis were low on days 17 and 18 and increased strikingly on day 19. This time sequence for development of LH-hCG receptors and steroid content of the testis was correlated exactly with the histological appearance of the endoplasmic reticulum characteristic of the differentiated Leydig cell. When fetal testes were examined at 12-h intervals between days 17 and 19, gonadotropin binding and testosterone content were closely correlated at all times studied. Thus, no dissociation between the two functions was demonstrable in the testis at any time during gestation. In the fetal ovary, LH-hCG binding and testosterone content were low or undetectable at all stages of gestation. These observations demonstrate a close temporal relationship between the appearance of the LH-hCG receptor and the synthesis of testosterone by the fetal testis and demonstrate that the histological and functional differentiation of the Leydig cell occurs within a few hours at approximately day 18 of gestation. The simultaneous appearance of LH-hCG receptors and testosterone synthesis in the gonad can be regarded as the biochemical manifestations of Leydig cell differentiation in the testis of the fetal rabbit.

Aging↗
PubMed2002

Osteopontin expression and regulation in the testis, efferent ducts, and epididymis of rats during postnatal development through to adulthood.

Osteopontin (OPN), a multifunctional phosphoprotein found in both hard and soft tissues, was examined in the male reproductive tract. The expression and regulation of OPN in the rat testis, efferent ducts, and epididymis was examined during postnatal development through to adulthood using immunocytochemistry at the light- and electron-microscopic level. Immunoblot analysis revealed a major 30-kDa band for epididymal tissue and a major 60-kDa band for the testis. In the testis, immunostaining of OPN was noted in early germ cells from spermatogonia to early pachytene spermatocytes, suggesting a role for OPN as an adhesive protein binding these cells to the basement membrane and adjacent Sertoli cells. Nonciliated cells of the efferent ducts expressed OPN, whereas a cell- and region-specific distribution of OPN was observed in the epididymis. Reactivity of OPN in the apical region of the cell corresponded to labeling of microvilli, small endocytic vesicles, and endosomes, where OPN may serve to remove calcium from the epididymal lumen and, thus, prevent mineral accumulation and subsequent decrease in sperm fertility. Regulation and postnatal studies revealed that circulating androgens regulate OPN expression in principal cells of the epididymis only. Taken together, the data reveal cell- and region-specific expression and regulation of OPN in the epididymis.

Aging↗