Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “testis”

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 829 records · Page 46Linked to original sources
PubMed1985

Assay system for simultaneous measurement of three steroidogenic enzyme activities in rat and human testis--effect of human chorionic gonadotropin.

An assay system that measures the enzymatic activities (17 alpha-hydroxylase, 17,20-desmolase, and 17 beta-hydroxysteroid dehydrogenase) in the delta 4 pathway of testosterone biosynthesis using rat and human testicular homogenate was examined. This system involves the simultaneous separation of the steroid intermediates by a three-step TLC procedure. The observed Rf values were 0.78 for progesterone (P), 0.59 for 17 alpha-hydroxyprogesterone (17 alpha-HP), 0.70 for androstenedione (A), 0.5 for testosterone, 0.64 for dihydrotestosterone, and 0.45 for 3 alpha, 17 beta-androstanediol. The identification of these steroid intermediates was further accomplished by acetylation and rechromatography of the representative samples along with the authentic standards and by recrystallization to constant specific activity until three consecutive crystallizations were within +/- 5% of the mean value. Incubation time up to 30 min and increasing protein concentrations showed a linear relationship with respect to these three enzymatic activities. The optimum temperature for these enzymatic activities varied from 32 to 34 degrees C, with a sharp decline between 37 and 40 degrees C. The Michaelis constants (Km) for the rat testis homogenate samples were 0.17 microM for P, 0.22 microM for 17 alpha-HP, and 2.5 microM for A, while for the human testis the Km values were 1.2, 2.2, and 2.3 microM, respectively, for these substrates. The concentrations of the endogenous steroid substrates present in these homogenate samples did not alter the Km or Vmax values. The effect of human chorionic gonadotropin (hCG) in vitro on these steroidogenic enzyme activities was also studied. In the rat testis, 10 IU of hCG produced a significant rise in all the three enzyme activities whereas in the human testis 10 and 30 IU of hCG showed no significant change in any of these enzymatic activities. However, 100 IU of hCG resulted in a significant increase in 17 alpha-hydroxylase and 17,20-desmolase activities in the human testis. These studies suggest that this assay system for the measurement of these enzymatic activities using a testicular homogenate sample provides consistent and reproducible results. Based on the sensitivities of the measurements and our experience with testicular biopsy technique, we conclude that a routine testicular biopsy in the human should provide sufficient tissue to run these enzymatic assays.

17-Hydroxysteroid Dehydrogenases↗
PubMed1989

Cell-specific metabolic activation of 7,12-dimethylbenz[a]anthracene in rat testis.

The binding of metabolites of the polycyclic aromatic hydrocarbon (PAH) 7,12-dimethylbenz[a]anthracene (DMBA) to protein in rat testis seminiferous tubules was studied. Treatment of cultured seminiferous tubule segments with DMBA resulted in very little binding to protein, suggesting that the seminiferous epithelium from rat testis lacks the cytochrome P-450-dependent monooxygenase(s) required for DMBA metabolism. In contrast, Leydig cells from rat testis contain monooxygenase systems which catalyze the metabolism of PAH, such as DMBA. This metabolic activation of DMBA was localized in both mitochondria and microsomes derived from Leydig cells and was decreased by inhibitors of the cytochrome P-450 system and by free radical scavengers, suggesting that the metabolism involved both cytochrome P-450 and free radical-dependent pathways. In the presence of whole Leydig cells or microsomes prepared from Leydig cells, the covalent binding of DMBA metabolites to protein of rat testis seminiferous tubules was increased 5- and 13-fold, respectively. These results suggest that DMBA is metabolized primarily in rat testis Leydig cells and that part of the produced metabolites find their way to the seminiferous epithelium, where they undergo further metabolism producing reactive metabolites, possibly cation radicals and diolepoxides, which interfere with the functions of spermatogonia and spermatocytes by modifying key proteins covalently.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

A search for trace expression of placental-like alkaline phosphatase in non-malignant human tissues: demonstration of its occurrence in lung, cervix, testis and thymus.

A search for placental or placental-like human alkaline phosphatase (ALP) was made in human tissues. The tissue extracts were assayed for ALP before and after heating at 65 degrees C for 1 h. Trace amounts of heat-stable ALP activity (greater than 0.01 IU/g) were found in lung, testis, cervix and thymus. The heat-stable ALP in these four tissues gave in Ouchterlony double diffusion plates lines of apparent identity with placental ALP when a rabbit anti-human placental antiserum was used. Inhibition studies with L-phenyl-alanine (Phe), L-homoarginine (Har), L-phenylalanylglycylglycine (Pgg), L-leucine (Leu) and levamisole (Leva), were carried out on the heat-stable ALP and on the total ALP. The heat-stable ALPs from cervix and lung gave [I]50 values with each inhibitor comparable to those of placental ALP. The heat-stable ALPs froM testis and thymus gave [I]50 values for Leu and Pgg which were significantly different from the placental isoenzyme. Electrophoresis of heat-stable lung ALP from different individuals showed polymorphic differences similar to those seen with placental ALPs. Such differences were not seen with heat-stable testis ALP. We conclude that human non-malignant testis, cervix, lung and thymus tissues contain small amounts of placental or placental-like ALPs. The heat-stable ALPs in cervix and lung appear to have the same characteristics as placental ALP and are probably encoded by the same gene locus. The heat stable ALPs in testis and thymus, though immunologically very similar to placental ALP differ from it in inhibition profile and electrophoretically. The significance of the results in relation to the "ectopic' expression of placental and placental-like ALPs in malignancy is discussed.

Alkaline Phosphatase↗
PubMed1987

Structure of the right testis of sexually mature genetically female fowl experimentally masculinized during embryonic life and submitted to a posthatching left castration.

Posthatching left castration of genetically female fowl, Gallus domesticus, preceded, during embryonic life, by a masculinizing treatment associating a testis graft and an antiestrogen resulted in the development of the right rudimentary gonad into a testis. Examined after the sexual maturity, the right testis of most treated animals was entirely composed of seminiferous tubules possessing a spermatogenic cell complement. Spermiogenesis proceeded to the stage of spermatozoon in 4 out of 17 treated animals and was almost as well organized as in a normal cock testis in 3 of them. Testis development appeared then as clearly improved, compared to that described previously in only left-castrated, with or without treatment with an antiestrogen, or only sex-reversed female fowl. The possible mechanism of this improvement is discussed.

Animals↗
PubMed1987

Effects of cryptorchidism and orchidopexy on deoxyribonucleoside-activated nucleotidase (DAN) in the rat testis.

1. Unilateral cryptorchidism was associated with an increase in specific DAN activity in the abdominal testis of adult rats. 2. In the scrotal, immature testis, there was an age-dependent decrease in specific DAN activity similar to that normally seen in rats. This decrease was less pronounced in the abdominal testis of unilaterally cryptorchid rats. 3. Total DAN activity in the abdominal testis showed a decrease in both immature and adult rats, when compared to that of the scrotal testis. 4. Orchidopexy following cryptorchidism in adult rats, resulted in complete restoration of DAN activity in spite of poor recovery of spermatogenesis.

Adenosine Triphosphate↗
PubMed1990

Secondary changes in the scrotal testis in experimental unilateral cryptorchidism.

Unilateral cryptorchidism was induced in under 2-day-old Wistar rat pups. A control group of rats underwent sham operation at the same age. The animals were killed at intervals from 5 to 120 days, both testes were excised, weighted, and processed for histological examination, morphometric measurement of the seminiferous tubules, and DNA flow cytometry. There was no difference in weight, Johnsen score, and tubular size between the scrotal testis of cryptorchid animals and control testes at any age. Significant decreases in all of these parameters occurred in the undescended testis from 30 days when compared with the scrotal testis in cryptorchid animals and controls. Using flow cytometry to measure changes in the DNA ploidy of the cells of the seminiferous epithelium during spermatogenesis, a significant decrease in the haploid population of cells occurred in the scrotal testis of cryptorchid animals at 40 days. This difference continued into adult life (P less than .005). Flow cytometry demonstrates a secondary decrease in spermatogenesis in the scrotal testis in experimental unilateral cryptorchidism.

Animals↗
PubMed1983

Intratubular localization of 4-ene-5 beta-reductase and 17 beta-hydroxy-dehydrogenase in immature golden hamster testis.

We have reported [1,2] in immature golden hamster testis that 5 beta-reductase is localized in the seminiferous tubules, while 5a-reductase is present in the interstitial tissue and that the 17 beta-ol-dehydrogenase activity is found predominantly in the seminiferous tubules. In the present study, we show the intratubular localization of these enzymes. The left testis of golden hamster was irradiated with 2000R or 8000R of X-rays at 22 days of age. The hamsters were killed at 28 days of age. Homogenates of the left irradiated and right intact testes were incubated with [14C]-4-androstone-3,17-dione and NADPH, and enzyme activity was estimated. Both testes were also examined histologically. The X-irradiation of the testis resulted in an almost complete disappearance of germ cells with a significant decrease in testis weight, but the interstitial tissue and tubular nongerm cells including Sertoli cells remained almost unchanged. However, the activities of 5 beta-reductase and 17 beta-ol-dehydrogenase expressed as nmol formed/testis/h did not decrease at all. These results show that 5 beta-reductase is localized in the tubular nongerm cells including the Sertoli cells and 17 beta-ol-dehydrogenase is present in the tubular nongerm cells and interstitial tissue in immature golden hamster testis.

17-Hydroxysteroid Dehydrogenases↗
PubMed1975

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↗
PubMed1987

Evidence for a free-radical-dependent metabolism of 7,12-dimethylbenz(a)anthracene in rat testis.

Polycyclic aromatic hydrocarbons, e.g., 7,12-dimethylbenz(a)anthracene (DMBA), cause various toxic effects in rat testis. To clarify the mechanism of action of DMBA in adult rat testis microsomes and mitochondria from this organ were investigated in vitro with respect to their capacity to metabolize DMBA. Qualitatively, both preparations showed DMBA-hydroxylase activities which were influenced by cytochrome P-450 inhibitors, chelators, and free-radical scavengers, suggesting that the DMBA metabolism was accounted for by different metabolic pathways in these organelles. Metabolism of DMBA was also accompanied by a pronounced covalent binding to both microsomal and mitochondrial protein, catalyzed primarily by a free-radical mechanism involving free or loosely bound iron which may involve superoxide anion shown to be generated by testis mitochondria. With microsomes covalent binding was markedly enhanced by added horseradish peroxidase but not by hydrogen peroxide whereas the mitochondrial binding was affected neither by added horseradish peroxidase nor by hydrogen peroxide. Antibodies raised against cytochrome P-450 c from rat liver inhibited the microsomal DMBA-hydroxylase but not the mitochondrial DMBA metabolism. It is concluded that the microsomal DMBA conversion and covalent binding are due to a mixture of cytochrome P-450 and free-radical-dependent metabolic pathways whereas the corresponding mitochondrial reaction is due mainly to a free-radical-dependent pathway. However, the data do not allow for a conclusion as to the quantitative importance of these pathways. It is proposed that both pathways may be important in DMBA-dependent testis toxicity but also in polycyclic aromatic hydrocarbon-dependent testis toxicity in general.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Effects of multiple injections of HCG on testis blood flow.

In attempting to determine whether or not multiple injections of human chorionic gonadotropin (hCG) augment testis blood flow, adult male rats were injected with three doses of 10 IU of hCG every other day and testis blood flow was determined on day 5, the day of the final injection. Testis blood flow (mL/100 g testis tissue/min +/- SEM) as measured by the 133Xe washout method increased from 10.8 +/- 1.3 to 20.4 +/- 4.5 (p less than 0.05) after the three doses of hCG. These observations suggest that multiple injections of hCG appear to have the same effect as a single dose of hCG in increasing testis blood flow. This supports the hypothesis that hCG should be administered to all patients undergoing orchiopexy in the hope that the increased perfusion of the gonad will make it less susceptible to ischemia during the surgical procedure.

Animals↗
PubMed1990

The testis and tissue transplantation: historical aspects.

Transplantation experiments involving the testis have been performed since the days of John Hunter, who transplanted a testis into the belly of a hen. The first person to use the testis as a site of transplantation appears to have been Sand, who found in 1919 that an ovary transplanted into the substance of the testis developed follicles. By 1970, there was considerable evidence that the testis under some circumstances was a relatively favorable site for graft survival. However, much of the evidence was equivocal, and the immunological privilege was by no means complete.

Animals↗
PubMed1987

Chromatographic characterization of dynorphin and [Leu5]enkephalin immunoreactivity in guinea pig and rat testis.

Tissues of the reproductive tract have been shown to contain mRNAs coding for pro-opiomelanocortin (POMC), pro-enkephalin and pro-dynorphin. However, the amounts of immunoreactive opioid peptides in these tissues are low, and in the case of the enkephalins and dynorphin, the molecular species responsible for the immunoreactivities have not been characterized. The chromatographic properties of dynorphin and enkephalin immunoreactivities in extracts of guinea pig and rat testis have therefore been determined. Dynorphin A and dynorphin B immunoreactivity was heterogeneous, with a significant amount attributable to high-molecular-weight forms. About 20% of the dynorphin A immunoreactivity, and about 40% of the dynorphin B immunoreactivity, in guinea pig testis extracts behaved as authentic dynorphin A or B, respectively during fractionation by ion exchange, gel filtration and high-performance liquid chromatography. Both high- and low-molecular-weight forms of [Leu5]enkephalin immunoreactivity were also present, with roughly 50-70% of the immunoreactivity attributable to low-molecular-weight forms. In extracts of guinea pig testis only a small part of this immunoreactivity eluted as authentic [Leu5]enkephalin during high-performance liquid chromatography. In rat testis most of the low-molecular-weight [Leu5]enkephalin immunoreactivity behaved as the authentic peptide. These results confirm that opioid peptides are produced in guinea pig and rat testis, and demonstrate that immunoreactive forms of the peptides similar to those found in brain and pituitary are present in the tissue.

Animals↗
PubMed1989

The protamine gene chromatin in developing trout testis exists in an altered state.

Micrococcal nuclease was used to probe the nucleosomal organization of the rainbow trout germ-line-specific protamine multi-gene family in testis and erythrocytes. In erythrocyte chromatin, the repressed protamine genes show a distinct nucleosomal repeat pattern. However, in early-stage testis chromatin, where the protamine genes are expressed, they lack a distinct nucleosomal repeat pattern, indicating that the disrupted chromatin structure is related to their transcriptional activity. Micrococcal nuclease-digested testis and erythrocyte chromatin was separated into soluble and insoluble fractions. Transcriptionally active/competent genes of testis that had been labeled by nuclear nick-translation were enriched in the low-salt eluted, micrococcal nuclease-sensitive chromatin fraction. This fraction was not enriched in protamine DNA sequences. In testis, but not erythrocytes, protamine DNA sequences were slightly enriched in chromatin that fractionated with insoluble nuclear material, suggesting that transcriptionally active protamine gene chromatin has an insoluble character. Since the different protamine genes may not be simultaneously expressed, our results show the distribution of both transcriptionally active and inactive protamine genes. However, our observations indicate that the active germ-line-specific protamine gene chromatin shares several, but not all, of the features associated with other active tissue-specific genes.

Animals↗
PubMed1993

Characterization of cDNAs encoding the rat testis-specific E1 alpha subunit of the pyruvate dehydrogenase complex: comparison of expression of the corresponding mRNA with that of the somatic E1 alpha subunit.

cDNA clones encoding the testis-specific form of the rat pyruvate dehydrogenase complex E1 alpha subunit have been isolated. Comparison of the predicted amino acid sequence with those of the somatic and testis-specific E1 alpha forms of man and mouse and the somatic E1 alpha form of rat indicates the change of a serine residue, believed to be phosphorylated in vivo by pyruvate dehydrogenase E1 alpha-specific kinase, to an alanine at position 233. The implications of this change are discussed. Northern blot analysis and RNase protection assays indicate that the expression of mRNA encoding testis-specific E1 alpha subunit is restricted to testis whereas mRNA for the somatic form is found in all tissues analyzed, albeit in very small amounts in testis.

Amino Acid Sequence↗
PubMed1988

Ribonuclease-RNAase inhibitor complex from rat testis. Purification of the RNAase inhibitor.

The RNAase inhibitor from rat testis has been purified to homogeneity. The purified protein appeared as a single spot after two-dimensional electrophoresis. The calculated Mr value is 48,000 which coincides with that obtained for the native protein on gel filtration chromatography, thus indicating a single polypeptide chain. The amino acid composition and the characteristics of the inhibitor activity are reported and compared to those of other RNAase inhibitors from mammalian tissues. The naturally occurring ribonuclease-RNAase inhibitor complex from rat testis has also been studied and compared with the rat testis inhibitor-RNAase A as model complex. The ribonuclease released from the natural rat testis complex showed heterogeneity of size. The significance of the rat testis ribonuclease/RNAase inhibitor system is discussed in terms of the important functionality of this organ.

Amino Acids↗
PubMedDate not supplied

Arginine vasopressin- and oxytocin-like peptides in the testis of two Australian marsupials.

High performance liquid chromatography (HPLC) and specific radioimmunoassay (RIA) for arginine vasopressin (AVP), mesotocin (MT), and oxytocin (OT) were used to identify and quantify these peptides in the testis of the brushtail possum (Trichosurus vulpecula) and the northern brown bandicoot (Isoodon macrourus). Arginine vasopressin (0.092 +/- 0.041 ng/g) and MT (0.198 +/- 0.089 ng/g), but not OT, were found in the possum testis, while the bandicoot testis contained AVP (0.061 ng/g), MT (0.108 +/- 0.024 ng/g), and OT (0.114 +/- 0.053 ng/g). The values correlate well with those reported for AVP- and OT-like peptides in the testis of eutherian mammals. It was concluded that there are neurohypophysial peptides present in the marsupial testis.

Animals↗
PubMed1987

Distribution and activation of protein kinase C in the rat testis tissue.

The distribution and role of the calcium-activated, phospholipid-dependent protein kinase C (PK-C) was studied in rat testis. When testis tissue was homogenized in the presence of 2 mmol/l EDTA and EGTA, the majority (greater than 70%) of the PK-C activity was soluble, the rest was released from the particulate fraction by solubilization with 0.3% Triton X-100. Without chelating agents the soluble PK-C activity was undetectable, and only partially recovered from solubilized membranes. Preincubation of the tissue with the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA, 10(-7) mol/l) translocated PK-C to the membranes, and the majority of this activity was recovered by solubilization. Mobility of testicular soluble PK-C activity in HPLC-DEAE cellulose chromatography was similar to that of the brain enzyme. This single step purified testicular PK-C activity 140-fold. The specific activity and subcellular distribution of PK-C was similar in whole testis tissue and separated seminiferous tubules (160-210 pmol 32P X mg protein-1 X min-1 in the soluble and particulate fractions), but 2- to 3-fold higher in purified Leydig cells. However, the majority of total testicular PK-C activity appeared to be of tubular origin. Unilateral cryptorchidism for 1 week reduced PK-C of the abdominal testis by 50%, and the activity of dissected seminiferous tubules varied according to the epithelial wave. Both findings suggest that the bulk of the activity resides in the seminiferous epithelium. Involvement of PK-C in Leydig cell function was demonstrated using the TPA, which at 10(-7) mol/l inhibited basal cAMP production by 50% (P less than 0.01) but increased that of testosterone by 2- to 3-fold (P less than 0.01). On the other hand, when incubated with hCG, TPA inhibited both cAMP and testosterone production; the ED50s of hCG stimulation increased 4- to 10-fold with both parameters. It is concluded that PK-C activity is present in both the seminiferous tubules and Leydig cells, and is involved in the regulation of these testicular compartments. Its total activity and subcellular distribution are at variance according to the functional state and endocrine milieu of the testis.

Animals↗
PubMed1995

Ontogeny of follicle-stimulating hormone receptor gene expression in the rat testis and ovary.

The ontogeny of the follicle-stimulating hormone (FSH) receptor (R) gene expression was studied in the rat testis and ovary between day 12.5 or 14.5 of fetal life (f), respectively, and adulthood. In Northern blots hydbridized with a cRNA probe corresponding to a part of the extracellular domain of the FSHR, specific hybridization to testicular RNA was detected from day f18.5, and to ovarian RNA from postnatal day 7 onwards. The main transcripts in the testis were at all ages 7.0 kb and 2.5 kb in size. In the ovary, the main transcript was always 2.5 kb in size. In order to increase the sensitivity of mRNA detection, the FSHR gene expression was also analyzed using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique with primer pairs corresponding to the near full-length FSHR mRNA or to its extracellular domain. The specificity of the PCR products was verified by Southern hybridization using a nested 32P-labeled cDNA probe. The results indicated that the expression of the extracellular domain of the FSHR was first detected on day f14.5 in the testis and on day f20.5 in the ovary. The full-length mRNA appeared in both sexes 2 days later, which is in agreement with earlier measurements of appearance of FSHR binding in the rat testis (day f17.5) and ovary (day 3 post partum). In situ hybridization using an antisense cRNA probe for FSHR demonstrated that, as early in development as specific hybridization was detected, it was confined to the Sertoli cells in the testis and to granulosa cells in the ovary. When compared with the developmental onset of the LHR gene expression (our earlier data), a major difference was observed in the ovary; the message encoding the extracellular LHR domain appeared > 10 days earlier than that corresponding to the full-length LHR message. In the case of mRNAs for the testicular LHR, and for FSHR of both sexes, the difference between the developmental appearance of the truncated and full-length RNA forms was only 2 days.

Animals↗