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 1,279 records · Page 71Linked to original sources
PubMed1989

Orchiopexy for intravaginal testicular torsion. Ring-shaped fixation of the lower part of the testis.

As a surgical therapy for intravaginal testicular torsion, we developed a testicular fixation method considering the testis in intravaginal testicular torsion in comparison with the normal one. With our method, the lower part of the testis is fixed in a ring form around the testicular long axis to show the wide extravaginal area similar to that of a normal testis. We believe that this method is simple, logical and effective to fix the testis in intravaginal testicular torsion.

Humans↗
PubMed1997

Loss of telomerase activity during male germ cell differentiation.

Although the activity of telomerase, an enzyme which synthesizes telomeres de novo and stabilizes telomere length has been demonstrated in the testis, the precise expression of activity in different germ cell types is not known. We examined telomerase activity using a PCR-based telomeric repeat amplification protocol during development of the rat testis from birth to adulthood. Telomerase activity was relatively high from birth to the 4th week of age, and then low between the 5th to 10th week, suggesting that the type A spermatogonial stem cells may be the population which is expressing the highest levels of telomerase activity. To ascertain which germ cells expresses the telomerase activity, purified populations of type A spermatogonia from 9-day old rats, and pachytene spermatocytes, round spermatids and epididymal spermatozoa from adult rats were isolated. While type A spermatogonia expressed very strong telomerase activity, the fractions containing pachytene spermatocytes and round spermatids also expressed telomerase activity, but at comparatively lower levels. Telomerase activity was totally absent in epididymal spermatozoa. Thus, it appears that the telomerase activity is expressed at high levels in the type A spermatogonial stem cells, is down-regulated during spermatogenesis, and is absent in the differentiated spermatozoa.

Animals↗
PubMed2002

Sertoli cell vacuolization and abnormal germ cell adhesion in mice deficient in an inositol polyphosphate 5-phosphatase.

The dynamic nature of cellular interactions during differentiation of germ cells and their translocation from the basement membrane to the lumen of the seminiferous tubules requires the existence of complex and well-regulated cellular adhesion mechanisms in the testis. Successful migration of the developing germ cells is characterized by dynamic breakage and reformation of cadherin-containing adherens junctions between the germ cells and Sertoli cells, the polarized somatic cells of the testis that support and nourish the developing gametes. Here, we demonstrate the accumulation of abnormally swollen, actin-coated, endosome-like structures that contain intact adherens junctions and stain positive for N-cadherin and beta-catenin in the Sertoli cell cytosol of mice deficient in Inpp5b, an inositol polyphosphate 5-phosphatase. Simultaneous to the formation of these abnormal structures, developing germ cells are prematurely released from the seminiferous epithelium and sloughed into the epididymis. Our results demonstrate a role for Inpp5b in the regulation of cell adhesion in the testis and in the formation of junctional complexes with neighboring cells, and they emphasize the important and essential role of phosphoinositides in spermatogenesis.

Animals↗
PubMedDate not supplied

Pituitary adenylate cyclase-activating polypeptide (PACAP): effects on blood flow in the testis and caput epididymidis of the rat.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is synthesized in developing germ cells in the testis and may act as a paracrine modulator of spermatogenesis and/or participate in tubule-interstitial interactions. Despite the abundance of PACAP in the organ, its role in testicular function has not yet been studied in vivo. Using laser Doppler flowmetry, the effects of PACAP on blood flow in the testis and caput epididymidis were studied on anesthetized adult rats. When given intratesticularly as 5- and 50-ng doses, PACAP increased blood flow by 55+/-21% (mean +/- SEM, P < 0.05) and by 68+/-11% at 5 mm from the injection site, respectively. Whereas 5 ng PACAP did not influence blood flow 15 mm from the site of injection, flow was reduced (-7+/-3; P < 0.05) at this site following treatment with 50 ng. Injection of 50 ng PACAP into the caput epididymidis increased epididymal blood flow by 18+/-4% (P < 0.05) at 1 mm from the injection site. None of the treatments above significantly affected the mean arterial blood pressure. Using immunohistochemistry, PACAP was observed in elongated spermatids and in the acrosomes of round spermatids in some, but not all, seminiferous tubules. Also, distinct PACAP immunoreactivity was seen in epithelial cells, particularly in clear cells, of the caput epididymidis. In conclusion, PACAP can induce vasodilatation in both testicular and epididymal microvessels and may be involved in regulating blood flow in these organs. Whereas the vasodilatory effect of PACAP is strong in the testis, the epididymal response appears to be more moderate.

Animals↗
PubMed1997

Sexual bipotentiality of developing ovaries in the terrestrial isopod Armadillidium vulgare (Malacostraca, Crustacea).

The androgenic glands (AG) of crustaceans are responsible for differentiation of male sexual characters. The process of gonadal differentiation in females was studied morphologically in Armadillidium vulgare given a masculinizing AG implant. Gonadal masculinization was induced by implantation of an AG into females at various stages of postembryonic development. Functional sex reversal always occurred when an AG was implanted into females that were in stages 5 and 6 of development. Partial formation of testes was induced after implantation of an AG into stage 7 and 8 females. When an AG was implanted into a stage 9 female, development of a functional testis was not observed, but the ovaries were partially masculinized. These results show that after the onset of sex differentiation female gonads retain sexual bipotentiality through several stages of postembryonic development. Implantation of one AG into a female is enough to induce gonadal masculinization and sex reversal in this species. The AG implant up to stage 6 (3.4 mm in body length) is an experimental procedure certain to transform a genetic female into a functional male. The process of gonadal development in female A. vulgare is discussed.

Androgens↗
PubMed1988

[Tissue culture studies on compensatory testicular hypertrophy of the young rabbit after hemicastration].

The regulation of compensatory testicular growth after hemicastration using prepubertal rabbits (less than 1000 g) was analyzed by weight increase of the remaining testis. At the 4th week postoperatively, the testis of hemicastrated rabbits weighed about 0.453 mg/g (testis weight/body weight) while the testis of sham operated rabbits weighed about 0.258 mg/g (testis weight/body weight). Thus, the testis of hemicastrated young rabbits developed compensatory growth up to about twice the size of control rabbit testis. This was further confirmed by the histological analysis of testes, in which the number of seminiferous tubules of hemicastrated rabbits was doubled as compared with the sham operated animal. The rabbit testicular cells obtained from the above operated testis could be cultured in monolayer form. These cultured monolayered cells were synchronized by culture in serum-free minimum essential medium (MEM) for 24 hrs. These primary rabbit testicular cells synthesized more DNA and RNA when cultured in a medium that contained hemicastrated rabbit serum, than in that containing normal serum. Stimulation of 3H-thymidine and 3H-uridine incorporation reached the maximum on the 4th day postoperation and thereafter DNA synthesis decreased rapidly whereas RNA synthesis decreased gradually. However, these cells cultured in MEM containing sham operated serum showed no significant increase in 3H-thymidine or 3H-uridine incorporation. Thus, the hemicastrated serum must contain a testis growth stimulating factor(s). Primary monkey testicular cells and primary rat testicular cells were treated with hemicastrated rabbits serum. The testicular cells of these animal species were insensitive to growth stimulation by the hemicastrated serum, which suggests that the testicular growth stimulation is species specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Gene expression changes induced in the testis by transplacental exposure to high and low doses of 17{alpha}-ethynyl estradiol, genistein, or bisphenol A.

The purpose of this study was to determine (1) the transcriptional program elicited by exposure to three estrogen receptor (ER) agonists: 17 alpha-ethynyl estradiol (EE), genistein (Ges), and bisphenol A (BPA) during fetal development of the rat testis and epididymis; and (2) whether very low dosages of estrogens (evaluated over five orders of magnitude of dosage) produce unexpected changes in gene expression (i.e., a non-monotonic dose-response curve). In three independently conducted experiments, Sprague-Dawley rats were dosed (sc) with 0.001-10 microg EE/kg/day, 0.001-100 mg Ges/kg/day, or 0.002-400 mg BPA/kg/day. While morphological changes in the developing reproductive system were not observed, the gene expression profile of target tissues were modified in a dose-responsive manner. Independent dose-response analyses of the three studies identified 59 genes that are significantly modified by EE, 23 genes by Ges, and 15 genes by BPA (out of 8740), by at least 1.5 fold (up- or down-regulated). Even more genes were observed to be significantly changed when only the high dose is compared with all lower doses: 141, 46, and 67 genes, respectively. Global analyses aimed at detecting genes consistently modified by all of the chemicals identified 50 genes whose expression changed in the same direction across the three chemicals. The dose-response curve for gene expression changes was monotonic for each chemical, with both the number of genes significantly changed and the magnitude of change, for each gene, decreasing with decreasing dose. Using the available annotation of the gene expression changes induced by ER-agonist, our data suggest that a variety of cellular pathways are affected by estrogen exposure. These results indicate that gene expression data are diagnostic of mode of action and, if they are evaluated in the context of traditional toxicological end-points, can be used to elucidate dose-response characteristics.

Animals↗
PubMed2003

A somatic role for eyes absent (eya) and sine oculis (so) in Drosophila spermatocyte development.

Interactions between the soma and the germline are a conserved feature of spermatogenesis throughout the animal kingdom. In this report, we find that the transcription factors eyes absent (eya) and sine oculis (so), previously shown to play major roles during eye development [Cell 91 (1997), 881] are each required in the somatic cyst cells of the testis for proper Drosophila spermatocyte development. eya mutant testes exhibit degenerating young spermatocytes. Mosaic analysis reveals a somatic requirement for both eya and so, in that neither gene is required in the germline for spermatocyte development. Immunolocalization analysis supports this somatic role, since both proteins are localized within cyst cell nuclei as spermatocytes differentiate from amplifying spermatogonia. Using antibodies against known cyst cell markers, we demonstrate that cysts of degenerating spermatocytes in eya mutant testes are encysted, ruling out a role for eya in cyst cell viability. Finally, we have uncovered a genetic interaction between eya and so in the testis, suggesting that, as in the eye, eya and so may form a transcription complex responsible for the activation of target genes involved in cyst cell differentiation and spermatocyte development.

Animals↗
PubMed2000

Morphological and functional variations of Leydig cells in testis of the domestic pig during the different biological stages of development.

The relationship of morphometrical and androgen receptor evaluations of the main testicular interstitium cellular element (Leydig cells) in the domestic pig provided interesting numerical and morphological features during the different aging stages. As early as 25 days (a period in which the pig is sexually immature) there was a low number of Leydig cells (1.46 x 10(8)) with respect to a 78% and 35% increase in the adult (2.48 x 108) and aged (1.78 x 10(8)) animal, respectively. Interestingly, when the volume density of Leydig cells was considered, the average volume of these cells seemed to be high (75%) in the aged pig with respect to the young immature animal whereas a lower increase (27%) was observed for the adult animal. Moreover, the evaluation of testosterone receptor binding sites in the testis at the various stages of development also displayed a differentiated pattern since elevated testosterone receptor binding levels of the high dissociation affinity type were obtained for the adult pig. Thus, from the combined morphological variations of Leydig cells and testosterone receptor binding activity, it appears that this androgenic receptor component exerts distinct autocrine effects on the different functional features of some testicular tissue constituents at the different aging stages of the domestic pig.

Age Distribution↗
PubMed1992

Sex determination and sex reversal: genotype, phenotype, dogma and semantics.

The genetic terminology of sex determination and sex differentiation is examined in relation to its underlying biological basis. On the assumption that the function of the testis is to produce hormones and spermatozoa, the hypothesis of a single Y-chromosomal testis-determining gene with a dominant effect is shown to run counter to the following observed facts: a lowering in testosterone levels and an increase in the incidence of undescended testes, in addition to sterility, in males with multiple X chromosomes; abnormalities of the testes in autosomal trisomies; phenotypic abnormalities of XX males apparently increasing with decreasing amounts of Y-chromosomal material; the occurrence of patients with gonadal dysgenesis and XY males with ambiguous genitalia in the same sibship; the occurrence of identical SRY mutations in patients with gonadal dysgenesis and fertile males in the same pedigree; and the development of XY female and hermaphrodite mice having the same genetic constitution. The role of X inactivation in the production of males, females and hermaphrodites in T(X;16)16H mice has previously been suggested but not unequivocally demonstrated; moreover, X inactivation cannot account for the observed bilateral asymmetry of gonadal differentiation in XY hermaphrodites in humans and mice. There is evidence for a delay in development of the supporting cells in XY mice with ovarian formation. Once testicular differentiation and male hormone secretion have begun, other Y-chromosomal genes are required to maintain spermatogenesis and to complete spermiogenesis, but these genes do not function effectively in the presence of more than one X chromosome. The impairment of spermatogenesis by many other chromosome abnormalities seems to be more severe than that of oogenesis. It is concluded that the notion of a single testis-determining gene being responsible for male sex differentiation lacks biological validity, and that the genotype of a functional, i.e. fertile, male differs from that of a functional female by the presence of multiple Y-chromosomal genes in association with but a single X chromosome. Male sex differentiation in XY individuals can be further impaired by a euploid, but inappropriate, genetic background. The genes involved in testis development may function as growth regulators in the tissues in which they are active.

Animals↗
PubMed1986

Electron microscopic and enzyme investigations of the testicular tissue in infertile males.

The ultrastructural characteristics of the testicular tissue in male infertility and the isoenzyme spectrum of some enzymes in sperm cells have been studied. The testicular material was taken by Vilar's method from three healthy males with normospermia and eleven males with hypogonadism, azoospermia and infertility. The material was treated by the routine methods for electron investigation and the observations were done with an electron microscope Opton EM 109. Horizontal electrophoresis of the testicular homogenate was done according to Nance. Malate dehydrogenetic activity (MDX) was rendered according to the method of Shaw and Prasad, and diaphoresis (DP) was carried out according to Brewer. It was found that spermatogenesis was interrupted at the pachytene stage at an ultrastructural level. Biochemical investigations showed that in the infertile testis two other atypical fractions appeared on diaphoresis, while at the malate dehydrogenase, a second fraction had considerably lower intensity as compared to the controls. It is pointed out that some profound disorders developing in the infertile testis affect mainly the germinal cells, which was proved at the ultrastructural level and also by the analysis of the isoenzymes MDH and DF key enzymes of carbohydrate metabolism.

Humans↗
PubMed2002

Charting the course of ovarian development in vertebrates.

The decision of the embryonic gonad to differentiate as either a testis or an ovary is a critical step in vertebrate development. The molecular basis of this decision has been the focus of much study, particularly over the past decade. Here we contrast the knowledge of early gonadal development and the switch to testis differentiation with the lack of molecular understanding of ovarian development at early stages. We review current knowledge regarding mechanisms of ovarian morphogenesis and propose a model for the hierarchical control of development of the fetal ovary, incorporating the few genes already known to be important and several signals or factors that are hypothesised to exist in the early ovary.

Animals↗
PubMed2004

Cell-cell interactions at the ectoplasmic specialization in the testis.

During spermatogenesis, the movement of developing germ cells across the seminiferous epithelium involves the restructuring of adherens junctions that form between Sertoli cells and between Sertoli and germ cells such as the ectoplasmic specialization (ES). At the ultrastructural level, the ES has been thoroughly studied for the past three decades. Until recently, however, relatively little has been known about the molecular architecture, not to mention the mechanism, that regulates the ES. Recent findings in the field have highlighted several areas of research that deserve attention in future studies. For example, proteins that constitute the ES can be targeted to compromise cell adhesion. This approach will not only provide a better understanding of ES dynamics, but also will yield innovative approaches for the development of male contraceptives.

Animals↗
PubMed1990

Management of the contralateral testis in patients with testicular germ cell cancer.

Patients with testicular germ cell tumours (TGCT) are at increased risk of developing a tumour in the contralateral testis. Such a tumour may be preceded by carcinoma in situ (CIS), which is more common in patients with infertility, atrophic testis or a history of cryptorchism. Of 1219 patients with TGCT seen at the Royal Marsden Hospital between 1962 and 1984 in whom the contralateral testis was managed by surveillance, 38 (3.1%) developed a second tumour and 8 died of germ cell tumours. Seventeen of 26 assessable patients (65%) exhibited at least one of the known aetiological risk factors for carcinoma in situ. Diagnosis of carcinoma in situ may lead to more appropriate management of the contralateral testis.

Carcinoma in Situ↗
PubMedDate not supplied

Ultrastructural observations of spermatogenesis in mice resulting from transplantation of mouse spermatogonia.

The objective of the present study was to provide a morphological characterization of spermatogenesis following germ cell transplantation into the seminiferous tubular lumen of another mouse. The recipient mice (W-locus) were sterile because of a defect in spermatogenesis resulting from the failure of virtually all germ cell precursors to migrate to the genital ridge during embryonic development. Recipient mice containing intratubular injections of testis cell suspensions from C57 mice were allowed to develop for over 1 year, whereupon animals were sacrificed and testis tissue examined by light and electron microscopy. Donor mouse cells formed normal cell associations (stages) as viewed in cross-sectioned tubules. Spermatogonia were found exclusively in the basal compartment, indicating that they were translocated from the tubule lumen through the Sertoli cell junctions, eventually to reside on the basal lamina. Some tubules looked entirely normal from both a quantitative and qualitative standpoint. Others showed qualitative and quantitative impairment. In some tubules a generation of cells was missing from a cell association. A variety of degenerating cells and structural abnormalities were responsible for this impairment, however, the most common abnormalities were seen during the elongation phase of spermatogenesis. Elongation abnormalities and the subsequent degeneration of these cells led to the presence of fewer-than-expected elongate spermatids. There were regions of the testis where no spermatogenesis was noted and only Sertoli cells were present. These regions were generally typical of the testis histology seen in animals not exposed to injected germ cells. However, Sertoli cells in these regions phagocytosed sperm produced in spermatogenically active regions of the tubules. Because transplantation of germ cells, either from fresh or from frozen cells, had wide-ranging implications in biology and medicine, characterization of spermatogonial transplants is an important step in improving this procedure.

Animals↗
PubMed1996

Sex determination in humans.

In mammals, the Y chromosome induces testis formation and thus male sexual development; in the absence of a Y chromosome, gonads differentiate into ovaries and female development ensues. Molecular genetic studies have identified the Y-located testis determining gene SRY as well as autosomal and X-linked genes necessary for gonadal development. The phenotypes resulting from mutation of these genes, together with their patterns of expression, provide the basis for establishing a hierarchy of genes and their interactions in the mammalian sex determination pathway.

Animals↗
PubMed1996

Sox9 expression during gonadal development implies a conserved role for the gene in testis differentiation in mammals and birds.

Heterozygous mutations in SOX9 lead to a human dwarfism syndrome, Campomelic dysplasia. Consistent with a role in sex determination, we find that Sox9 expression closely follows differentiation of Sertoli cells in the mouse testis, in experimental sex reversal when fetal ovaries are grafted to adult kidneys and in the chick where there is no evidence for a Sry gene. Our results imply that Sox9 plays an essential role in sex determination, possibly immediately downstream of Sry in mammals, and that it functions as a critical Sertoli cell differentiation factor, perhaps in all vertebrates.

Amino Acid Sequence↗