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Steroid entry into rete testis fluid and the blood-testis barrier.

Evidence that steroids enter rete testis fluid (RTF) from the blood at varying rates was obtained during i.v. infusions into rats. Testosterone and dehydroepiandrosterone were readily transferred into the fluid, whereas cholesterol was excluded. Between these extremes, the appearance of radioactivity in the RTF suggested the following order of entry rate: progesterone greater than pregnenolone greater than 5-alpha-reduced androgens greater than oestrogens greater than corticosteroids. Preliminary identification of metabolites in RTF and blood suggested that testosterone and dehydroepiandrosterone were transferred largely unchanged. Androstenedione and progesterone, however, were largely metabolized during transfer into the RTF, the former being transformed to testosterone. The results are used to discuss the nature of the blood-testis barrier to steroids and the source of androgens in the RTF.

Androgens

Kinetics of the enzymatic pattern in the testis. I. Stage dependence of enzymatic activity and its relation to cellular interactions in the testis of the Wistar rat.

The "morphology" of the enzymatic activities of thiamine pyrophosphatase (TPPase), acid phosphatases (ACPases), adenosine triphosphatase (ATPase) and steroid-3 beta-ol dehydrogenase (St-3 beta-ol DH) has been described using as a basis the classification of the seminiferous epithelium of the rat into 14 stages as proposed by Leblond and Clermont (1952a, b). It was demonstrated (Figs. 1, 2) that 1. the kinetics of the enzymatic pattern is correlated with the developmental stages during spermatocyto- and spermiogenesis, and that therefore the chemocytostructure, especially of the germ cells, shows characteristic changes. 2. the enzymatic pattern yields information on the chemohistostructure of the testis, and thus indicates interactions between the germ cells and the coordinated somatic cells. This is valid especially for the behaviour of the "marker enzymes" TPPase and ACPases. Initially the activity of both enzymes is distributed in the cytoplasm: TPPase appears in stage VII in the preleptotene spermatocytes, and ACPases appear in stage VII in the pachytene spermatocytes. In the following stages the activity of TPPase and ACPases increases and becomes more and more concentrated, i.e. from stage IX to XIV and thereafter from stage I to XIII in the case of TPPase, and from stage I to XIII in the case of ACPases. Finally the enzymatic activity of both TPPase and ACPases is arranged in spherical bodies near the nucleus of the spermatocytes. Thus the late pachytene and diplotene spermatocytes, as well as the spermatocytes in diakinesis, are characterized by deeply stained spherical dots covering the region of the Golgi apparatus. Both enzymes disappear during the maturation divisions--parts of the cytoplasm of the II-spermatocytes during interphase react weakly positive--, reappear in the Golgi region of the newly formed spermatids in stage I, remain there up to stage V in the case of ACPases, and up to stage VII in the case of TPPase. From stages VIII to XIV TPPase is weakly positive in the Golgi apparatus of the elongating spermatids, moving within the cytoplasm from the head region towards the tail. Finally they appear in the cytoplasm of the Sertoli cells: (1) ACPases appear in the borderline region between the Sertoli cells and the elongated spermatids in stages XII to XIV (2) TPPase first appears in the basal region of the Sertoli cells in stages XI to XIV, and becomes positive in the subsequent stages I to IV as "streamer like" bands from the basement membrane up to the heads of the elongated spermatids. Both enzymes disappear gradually during stages I to III and IV to V respectively. Stage dependence of ATPase can be observed in the apical region of the Sertoli cells around the heads and the middle pieces of the elongated spermatids. ATPase appears for the first time in stages IX to X, and becomes increasingly more and more concentrated and condensed up to the point when the newly formed spermatozoa are released in stage VIII...

3-Hydroxysteroid Dehydrogenases

Post-translational modification of proteins in the human testis development pathway.

BACKGROUND: The foetal testes produce the androgens necessary to masculinise the developing embryo and support the maturation of germ cells, that will eventually develop into sperm, thus ensuring future reproductive capacity. The testes develop from the bi-potential gonads in a highly orchestrated process resulting in the differentiation of a complex tissue with multiple cellular lineages. While recent transcriptomic and chromatin-based analyses of human foetal testes have provided an unprecedented level of insight into signalling pathways activated during this process, proteomic studies of the human foetal gonads remain limited. Proteins are active molecules and post-translational modification (PTM) of proteins influences protein activity, stability and localisation. Studies have shown that PTMs regulate critical proteins in testis development, and their disruptions are implicated in congenital disorders including differences of sex development (DSD), in which sex development is atypical. Despite this, the role and regulation of protein PTM during human testis development remains poorly understood due to limited access to human foetal gonadal tissue, a paucity of large-scale proteomics studies, and a lack of robust of human gonad in vitro models. OBJECTIVE AND RATIONALE: This review aims to provide a comprehensive analysis of validated PTMs affecting proteins critical for testicular development. We discuss PTMs with evidence for a role in normal testis development, and highlight those disrupted in DSD. We review emerging techniques, including proteomic technologies and organ modelling systems that may advance our understanding of PTMs in foetal testis development. We discuss challenges that have restricted the application of these technologies and how overcoming these will significantly improve our understanding of testis development and disease, diagnostics and patient outcomes. SEARCH METHODS: We searched PubMed and the University of Melbourne library for peer-reviewed English-language studies using keywords such as phosphorylation, SUMOylation, acetylation, ubiquitination alongside each protein of interest. PTM sites in proteins involved in testis development were identified using the PhosphoSitePlus database focusing those confirmed in in vitro or animal model studies. ClinVar and the Human Gene Mutation Database were used to identify patient variants that may disrupt PTM sites. OUTCOMES: Our review finds that proteins required for human foetal testis development are subject to extensive PTM. Several PTM sites and PTM-mediated pathways [e.g. MAPK (mitogen-activated protein kinase) pathway] are disrupted in patients with DSD or related conditions. While recent advances in proteomics technologies hold considerable promise, their application to human foetal gonads has been constrained by technical, ethical, and logistical challenges. Encouragingly, emerging high-sensitivity and low-input technologies, alongside stem cell-based approaches, offer viable pathways to overcoming these barriers. WIDER IMPLICATIONS: The relationship between gene regulation, protein expression, and cellular outcome is inherently non-linear, shaped by additional regulatory layers-most notably PTMs. The contribution of PTMs to human testis development in both typical and atypical contexts is a major knowledge gap. Addressing this gap has broad clinical and biological relevance: it may help improve genetic diagnosis or shed light on how proteins or pathways critical for testis development respond to environmental signals-an increasingly pressing question as declining global fertility rates bring testicular function under greater scrutiny. REGISTRATION NUMBER: N/A.

Humans

Endogenous steroid production in cellular and subcellular fractions of rat testis after prolonged treatment with gonadotropins.

Steroid production and enzyme activities were examined in preparations of whole testis tissue, isolated interstitial tissue and seminiferous tubules obtained from adult rats with intact pituitaries receiving daily subcutaneous injections of 100 I.U. human chorionic gonadotropin for 5 days and from control animals. After human chorionic gonadotropin administration testosterone concentrations were increased in total homogenates of whole testis tissue, interstitial tissue and seminiferous tubules. The testosterone production from endogenous precursors was enhanced only in total homogenates of whole testis tissue and interstitial tissue obtained from testes of human chorionic gonadotropin-treated rats. The production of testosterone in the corresponding homogenates of isolated seminiferous tubules was very low. The specific activity of 3 beta-hydroxysteroid dehydrogenase was increased in total homogenates of whole testis tissue, isolated interstitial tissue and seminiferous tubules. No effect was observed on the specific activities of marker enzymes such as cytochrome c oxidase, monoamine oxidase, steroid sulfatase and lactate dehydrogenase, whereas the specific activities of carboxyl esterase were decreased in homogenates of whole testis tissue and interstitial tissue. Total activity of monoamine oxidase was increased in homogenates of interstitial tissue of tests from human chorionic gonadotropin treated rats. After the same prolonged human chorionic gonadotropin treatment the concentration of pregnenolone was increased in mitochondrial fractions of whole testis tissue, interstitial tissue and seminiferous tubules, and the amount of protein isolated in the mitochondrial fraction of interstitial tissue increased by 40%. Steroid production (estimated as pregnenolone) from endogenous precusors by mitochondrial fractions of whole testis tissue and interstitial tissue were increased after human chorionic gonadotropin treatment, for whole testis from 580 pmol/mg mitochondrial protein per h to 1420 pmol/mg per h; and for interstitial tissue from 2665 pmol/mg per h to 7050 pmol/mg per h. The production of pregnenolone in mitochondrial fractions obtaine from isolated seminiferous tubules was very low and contributed hardly at all to the total pregnenolone production in mitochondrial fractions of whole testis tissue from normal rats as well as from human chorionic gonadotropin-treated rats.

Animals

Clinical implications of gonadal venography in the management of the non-palpable undescended testis.

Selective gonadal venography was used on 28 patients with a total of 34 non-palpable undescended testes. The data obtained in this study suggest that 1) an internal spermatic vein with a pampiniform-like plexus indicates the presence of a testis, 2) a blind-ending vein on venography suggests the absence of a testis, 3) an internal spermatic vein or vas deferens may be present without a testis, 4) a testis probably cannot be present without a gonadal vein, 5) a testis may be present without a vas, 6) a blind-ending vas deferens does not necessarily indicate the absence of a testis and 7) a blind-ending vas deferens in a patient in whom a blind-ending gonadal vein is localized to the same region probably indicates the absence of a testis. Gonadal venography may localize a non-palpable undescended testis or suggest testicular agenesis. In addition, gonadal venography has aided in the selection of the operative approach and, in the future, may provide criteria under specific circumstances for determining whether an operation is necessary and, if so, the extent of surgical exploration.

Adolescent

Tissue guanosine-3',5'-cyclic monophosphate levels and soluble guanylate cyclase activity: a positive correlation during unilateral cryptorchidism in the rat testis.

The relationship between the subcellular distribution of guanylate cyclase and tissue guanosine-3',5'-cyclic monophosphate (cGMP) levels was investigated in rat testes after surgically induced unilateral cryptorchidism. Placement of one of a testis pair in the abdominal cavity results in loss of testicular weight and function in the abdominal testis whereas the remaining scrotal testis appears to be functionally normal. Within 5 days after surgery, tissue cGMP levels were increased by twofold in the abdominal testis. A fourfold elevation was noted from 10 to 30 days after surgery. Whereas the homogenate guanylate cyclase activity was only slightly elevated 10 and 20 days postoperatively, a 200% increase in the soluble guanylate cyclase activity was seen at 5 days. Between 10 and 30 days, the rise in activity was >250% (P < 0.01). An increase in soluble guanylate cyclase activity was noted when the data were expressed as per milligram protein, per milligram DNA or per whole testis. Conversely, particulate guanylate cyclase activity was reduced by 40% in the cryptorchid testis. Kinetic analysis of the soluble enzyme prepared from abdominal and scrotal testes yielded linear Line-weaver-Burke plots for both enzyme preparations with an identical K(m) for guanosine triphosphate, but a three-fold higher maximal velocity for the abdominal enzyme. When the soluble guanylate cyclases from both testes were mixed and assayed together, the activities were additive rather than exhibiting synergism or inhibition. These experiments indicate that the altered V(max) is not due to a transferable activator or inhibitor.An immunocytochemical technique was used to assess the cell type in which the alterations in cGMP metabolism occurred. Comparison of the scrotal and abdominal testes revealed that the abdominal testis exhibited enhanced cGMP immunofluorescence within the cells lining the inner aspect of the seminiferous tubule as well as tubular elements and interstitial cells. Thus, it is inferred that the correlated changes in soluble guanylate cyclase activity and cGMP levels occur in several of the cell types that remain viable within the cryptorchid testis.

Animals

Clinical implications of gonadal venography in the management of the non-palpable undescended testis.

Selective gonadal venography was used on 28 patients with a total of 34 non-palpable undescended testes. The data obtained in this study suggest that 1) an internal spermatic vein with a pampiniform-like plexus indicates the presence of a testis, 2) a blind-ending vein on venography suggests the absence of a testis, 3) an internal spermatic vein or vas deferens may be present without a testis, 4) a testis probably cannot be present without a gonadal vein, 5) a testis may be present without a vas, 6) a blind-ending vas deferens does not necessarily indicate the absence of a testis and 7) a blind-ending vas deferens in a patient in whom a blind-ending gonadal vein is localized to the same region probably indicates the absence of a testis. Gonadal venography may localize a non-palpable undescended testis or suggest testicular agenesis. In addition, gonadal venography has aided in the selection of the operative approach and, in the future, may provide criteria under specific circumstances for determining whether an operation is necessary and, if so, the extent of surgical exploration.

Adolescent

Testis antigens of man and some other primates.

Rabbit antisera raised aginst testis preparations of human, chimpanzee, rhesus monkey, and baboon origin were used to study testis-specific antigens within and among the four primate species. Antisera were absorbed with serum, liver, kidney, and spleen preparations of the respective species against which they had been produced. Immunoelectrophoretic analysis of testis extracts, using the absorbed antisera, indicated the following minimum numbers of testis-specific antigens for each species: man, 10; chimpanzee, 8; rhesus monkey, 10; and baboon, 8. Most of the testis antigens were cross-reactive among species. The results suggest that human spermatozoa possess at least four to five specific antigens which originate in the testis. The antigen that induces sperm-immobilizing antibody cross-reacted among the four species of primates. Human and rhesus monkey sperm reacted equally in the immobilization system. Testis extracts from each primate species were capable of removing the sperm-immobilizing activity of human immune sera by absorption. Testis proteinase activity, as determined by using a gelatin membrane substrate, was inhibited by the gamma-glogulin fractions of rabbit and rhesus monkey antisera and also appeared to be cross-reactive among the species.

Animals

[Tumours of the undescended testis (author's transl)].

It has now been clearly demonstrated that cryptorchidism is accompanied by a very marked increase in malignancy of the ectopic testis as well as in that in place. Amongst 80 patients undergoing surgery for carcinoma of the testis 14 (17.5%) had a past history of unilateral undescended. The risk of malignancy developing in an ectopic testis is 12 to 48 times greater than that of a testis which has descended normally. It would appear that the higher the position of the testis, the greater is the risk. Orchidopexy may decreased the risk if performed before the age of 11. When the tumour is situated in an ectopic testis, the clinical picture is often misleading. When the ectopic testis has been brought down the special feature of these tumours is the frequency of spread to inguinal lymph nodes. In terms of its basic principles the treatment of these tumours does not differ from that of those affecting normal testis. The aetiology of these tumours remains uncertain. There would seem to be a consensus in favour of a disgenetic origin, possible secondary to hormonal deficiency.

Adult

Distribution and fine structure of the lymphatic system in the human testis.

The distribution of lymph vessels in the human testis was investigated using ink injection methods, and light and electron microscopy. Lymph capillaries occur in the septula testis but are absent in the intertubular tissue. They consist of endothelial cells provided with an incomplete basal lamina and anchoring filaments of the adjacent connective tissue. Frequently, the endothelial cells are separated by gaps measuring up to 2 micron. The lymph capillaries of the septula testis are connected to lymph vessels in the rete testis and tunica albuginea. These vessels have occasional smooth muscle cells and valves. At the posterior margin of the testis, the network of lymph vessels merges into collecting ducts, which together with vessels derived from the rete testis are drained by the lymphatic system in the spermatic cord.

Endothelium

Further studies on the effect of cyclic nucleotides on testis DNA synthesis.

The inhibitory effect of dibutyryl cyclic AMP (dbcAPM) on in vitro rat testis DNA synthesis appears to be relatively specific in nature. Of 7 organs studied, only testis and kidney in vitro DNA synthesis was significantly affected. In addition, another cyclic nucleotide, dibutyryl cyclic GMP (by dbc AMP), had no effect on in vitro testis DNA synthesis. This was true whether testis tissue was mature or immature. Similarly, by dbcAMP had no significant effect on in vitro testicular protein or RNA synthesis. The inhibition of in vitro testicular DNA synthesis by dbcAMP occurs while 3H-cAMP is accumulating in testis tissue. dbcGMP was found to have no antagonistic effect towards the inhibitory effect of dbcAMP on in vitro testis DNA synthesis.

Aging

Torsion of the testis and allied conditions.

In 15 years at Bristol there have been 293 cases of torsion of the testis, 55 cases of torsion of a testicular appendage and 5 cases of testicular ischaemia due to other causes. The risk of a male developing torsion of the testis or its appendix by the age of 25 is about 1 in 160. Both conditions occurred primarily in adolescents, but among prepubertal boys torsion of an appendage was as common as torsion of a normally descended testis. There was a slight left-sided preponderance in testicular torsion, more marked in torsion of the appendages; the incidence of bilateral torsion was 2-0 and 1-8 per cent respectively. The clinical features and differential diagnosis of the two conditions are compared. Torsion of a testicular appendage is the most commonly misdiagnosed scrotal lesion, the preoperative diagnosis being correct in only 11 per cent of cases compared with 90 per cent for torsion of the testis. Twenty-one cases of recurrent torsion underwent prophylactic bilateral orchidopexy. There were 20 cases of torsion of undescended testes, with a salvage rate of only 20 per cent. The overall testicular survival rate was 55-3 per cent. Viability depends upon the possibility of spontaneous reduction, the preoperative delay after the onset of symptoms, the degree of torsion of the cord and the length of follow-up in doubtful cases. Urgent scrotal exploration is advised in every case of acute testicular pain unless there is overwhelming evidence of epididymoorchitis. Exploration of the opposite side is mandatory in torsion of the testis and advisable in torsion of an appendage.

Adolescent

Androgen receptor in nuclei of rat testis.

Testis nuclei of hypophysectomized rats selectively accumulate labeled testosterone and 5alpha-dihydrotestosterone following the injection of tritiated testosterone in vivo. Testosterone and 5alpha-dihydrotestosterone are bound to macromolecules in nuclei and can be extracted with 0.5 M KCl. Accumulation of protein bound radioactive androgens in nuclei of isolated seminiferous tubules is similar to that of whole testis. The relative amounts of testosterone and dihydrotestosterone in purified nuclei were similar to the relative amounts bound to cytoplasmic receptors, suggesting that cytoplasmic androgen-receptor complexes may be transported into the nuclei. Binding of labeled androgen is saturable and inhibited by prior injection of unlabeled testosterone or cyproterone acetate. Nuclear binding sites are destroyed by the proteolytic enzyme pronase, but not by DNase. Like the cytoplasmic androgen-receptor complexes in rat testis, nuclear androgen-protein complexes are heat labile and dissociate slowly at 0 degrees C. androgens fail to accumulate in testis nuclei of the Stanley-Gumbreck androgen insensitive rat, a species lacking cytoplasmic androgen receptors in testis and other androgen target tissues.

Animals

[Surgical technique in the management of undescenced testis (author's transl)].

In cases of retentio abdominalis or inguinalis and of ectopic testis, surgery is performed about the 2nd year of life. Essentials of the operating technique are: incision of the skin must not be parallel to the spermatic cord; testes and spermatic cord must be mobilized without trauma; ideally a biopsy of the testis should be taken; any pulling of the spermatic cord and torsion of it during fixation of the testis should be avoided. If initial tensionfree placement of the testis in the scrotum is impossible, the operation should be carried out in 2 sessions with an interval of 6-12 months. In 241 cases of children operated on from 1972-1975 with 308 total operations, the author observed 2 recurrences and 1 deep infection (scrotal abscess).

Adolescent

[Long-term study on the influence of running exercise, food restriction, running exercise + food restriction and of parenterally applicated testis cells on age-parameters of the rat (author's transl)].

Preliminary results of a long-term study on 1100 male Sprague-Dawley rats are presented, showing the influence of running exercise, of restricted diet, of both of these together and of the s.c. application of lypholized testis cells. Up to now animals aged 9, 15 and 24 mths were investigated. The test-animals were exposed to the experimental conditions from their 6th month of life. The running exercise was carried out on a treadmill (30 m at a speed of 25 m/min, horizontal) 5 days a week. A food restriction of about 20% was achieved by 2 fasting-days a week. The lyophilized testis cells were injected for the first time at an age of 9 mths and afterwards in 6 mths intervals. Between the injection and the assessment of the age-parameters there was an interval of 6 mths. S o fare the following parameters of the comprehensive test-program have been evaluated: 1) running performance in m (treadmill, 20 m/min, ascent 15 degrees), 2) motor activity (Animex Activity Meter), 3) chemical contraction-relaxation of tail-tendon-fibers, 4) total lipids and total cholesterol in the plasma. The results obtained so far show that a mild regular training, moderate food restriction and the s.c. application of testis-cells are able to cause a significant shift in the dirction of a younger biological age in at least some of the age parameters. The action of the testis-cells seems to affect most of the age parameters but shows the tendency to be more distinct at a higher age. More concrete statements about the influence on the biological age or the vitality will only be possible after the multivariate analysis of the results.

Age Factors

Agenesis or atrophy of the testis and vas deferens.

In this study the author examines the relationship between agenesis or atrophy of the testis and of the vas deferens. From a prospective study of 237 cases of unilateral and bilateral undescended testis, 12 cases of agenesis of a testis were seen; 9 of the 12 cases were associated with agenesis of the vas deferens and in 3 of these unilateral renal agenesis was also present, not necessarily ipsilaterally. Three other cases of testicular agenesis and four cases of extreme testicular atrophy were seen. In all seven, the vas deferens was present in part or in its entirety and roentgenography disclosed a normal upper urinary tract. Agenesis of the vas deferens was seen only in patients with monorchism. No patient was anorchid. It is concluded that an important link exists between agenesis of the vas deferens and agenesis of the testis.

Abnormalities, Multiple