Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following Northern analysis, GGT mRNA was found predominantly within the caput epididymides and kidney. The size of mRNAs for kidney, caput, corpus, and ductus deferens were 2.2, 2.3, 2.2, and 2.3 kb, respectively, whereas cauda showed a doublet of 2.2 and 2.3 kb. GGT transpeptidation and hydrolytic activity within epididymal luminal fluids collected by micropuncture showed caput = corpus greater than cauda and corpus greater than caput greater than cauda, respectively. Caput luminal GGT transpeptidation activity was significantly inhibited by serine-borate and was optimal at pH 8.0. The calculated Km and Vmax values for hydrolysis of GSH by caput luminal GGT were 0.06 microM and 2.19 nmoles/min/microliters luminal fluid at pH 8.5 compared to 0.49 microM and 0.49 nmoles/min/microliters luminal fluid, respectively, at the physiological pH 6.5 of caput fluid. These studies would suggest that the epididymis can control the activity of luminal GGT by pH. Lower Km (0.12 microM) and higher Vmax (1.13 nmoles/min/microliters luminal fluid) values were also calculated when GSSG was used compared to GSH. Results from Triton X-114 partitioning experiments suggest that luminal GGT probably exists in both membrane bound and nonmembrane bound forms. Western blot analysis of proteins within epididymal luminal fluids revealed both subunits of GGT in all epididymal regions studied. However, two lower molecular bands, approximately 22 kDa and 21 kDa, were also observed in cauda fluid. It is suggested that as GGT is transported along the epididymal duct it undergoes degradation, which accounts for its loss of activity in the distal epididymal regions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression and activity of gamma-glutamyl transpeptidase in the rat epididymis. 167 40

75Se was given intravenously into 5 bulls. Multiple blood and semen samples were taken and during slaughter 5, 10, 15, 20 and 80 days later samples of various reproductive and other organs were collected. After injection, 75Se in blood reached a peak at 6 h followed by a rapid decline. The label was mainly found in serum with very low levels in erythrocytes. Initially the serum 75Se was bound to a macromolecule with a mw of 80 kDa, but later a larger molecule (100 kDa) was observed. In semen 75Se was first mainly found in seminal plasma, where a plateau level was reached at 5 d followed by a gradual decline after 12 d. The total semen level, however, increased after 14 d and this increase was due to a rapid appearance of the label in spermatozoa. The sperm 75Se level reached a plateau at 20 d and remained high until 40 days, after which a gradual decline ensued. The seminal plasma 75Se eluted in gel filtration coincident with glutathione peroxidase. The highest levels of 75Se were found in the kidney followed by seminal vesicles and testicles. The seminal vesicle secretion was particularly rich in 75Se and its fractionation resembled that of the seminal plasma. 75Se appeared in the epididymal caput within 5 days and passed through the epididymis in 20 days. It is concluded that 75Se is actively incorporated in the bull seminal vesicles into GSH-Px, while in the testis it is incorporated into a structural sperm protein during spermatogenesis.
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PMID:Incorporation of selenium-75 into seminal plasma and spermatozoa of the bull. 228 76

gamma-Glutamyl transpeptidase (gamma-GT), its substrate (GSH) and hydrolytic product (L-glutamic acid) were measured biochemically in mouse reproductive tissues. The epididymal caput and seminal vesicles showed the highest specific activities of gamma-GT, while GSH and L-glutamic acid were widely distributed in all tissues. Histochemically, gamma-GT displayed a strong apical and supranuclear reaction and a moderate basal activity in the ductuli efferents, a weak luminal reaction in the first, a moderate apical reaction in the second and a strong apical and supranuclear reaction in the third segment of the epididymal caput. In the epididymal corpus and cauda, the gamma-GT reaction was confined to the tubular lumina but an apical reaction was also present in the cauda. The daily administration of acivicin (12 mg/kg body weight), an irreversible inhibitor of gamma-GT, for 14 days resulted in a 60% suppression of the enzyme activity in the epididymal caput, while the gamma-GT inhibition in the kidney was greater than 95%. The treatment caused no change in the activity of alanyl aminopeptidase. Histochemically, the basal and supranuclear gamma-GT activities in the ductuli efferents and the third epididymal segment were suppressed, but the apical reactions were maintained. The in-vivo suppression of epididymal gamma-GT activity may have implications in the control of post-testicular sperm maturation.
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PMID:Distribution of gamma-glutamyl transpeptidase in the mouse epididymis and its response to acivicin. 256 39

A method was developed to selectively deplete glutathione (GSH) in a single rat testis. Using intratesticular injections of a mixture of two GSH-depleting agents, diethylmaleate and buthionine sulfoximine, testicular GSH levels were decreased to 33-54% of control 2 hr after injection and remained suppressed for 24 hr. GSH levels in the contralateral testis and liver were not affected by this treatment. Comparisons between GSH-depleted and vehicle-injected (contralateral) testes, evaluated 2 weeks later, showed that although testis and epididymal weights and cauda epididymal sperm reserves were slightly reduced (to greater than or equal to 90% of controls), no changes were seen in testicular spermatid counts or in the morphology or motility of cauda epididymal sperm. An increase in histologically abnormal tubules localized to the injection site occurred in some GSH-depleted testes; however, the proportion of normal tubules containing step 19 spermatids was not affected. Thus, intratesticular injections of GSH-depleting agents selectively lowered GSH levels in the treated testis, with minimal adverse effects. This protocol can now be applied to investigate specific roles of GSH in the testes, particularly with regard to the possible modulation of the effects of testicular toxicants.
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PMID:Unilateral depletion of testicular glutathione levels in the rat following intratesticular injections of diethylmaleate and buthionine sulfoximine. 271 98

Buthionine sulfoximine (BSO) treatment significantly reduced testicular epididymal and vas deferens glutathione (GSH) levels in rats. Testicular levels of GSH were reduced by 20%, while epididymal GSH levels were reduced by more than 50%. BSO treatment correspondingly enhanced ethyl methanesulfonate (EMS)-induced dominant lethal mutations. EMS-induced resorption rates were doubled following BSO treatment. This effect was observed in mating wk 2 and 3 (d 8-19 following treatment), indicating effects on those germ cells which were in late testicular stages or were caput epididymal spermatozoa at the time of EMS treatment. The enhancement of the mutagenic action of EMS by BSO is restricted to the same time period (spermatid-spermatozoa transition, early epididymal maturation) as maximum sensitivity to the clastogenic action of EMS on male germ cells. The temporal pattern of EMS alkylation of rat spermatozoa correlated with the incidence of EMS-induced dominant lethal mutations. BSO depresses GSH in the male reproductive tract in a dose- and time-dependent manner. Perturbation of GSH in the male reproductive tract appears to influence chemical-induced germ cell mutations.
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PMID:Depression of glutathione in male reproductive tissues and potentiation of EMS-induced germ cell mutagenesis by L-buthionine sulfoximine. 289 64

The distribution of glutathione (GSH), L-glutamic acid (Glu) and gamma-glutamyl transpeptidase (gamma-GT) was studied in bull reproductive organs and fluids. Glutathione, the physiological substrate of gamma-GT, was localized specifically by a fluorescence method in the testis, epididymis and spermatozoa. Of the reproductive tissues, the testis, caput epididymis and ampulla had the highest levels of GSH, but it was also present in seminal fluid. Washed caput epididymal sperm had three times the GSH content of cauda epididymal or ejaculated sperm. In spermatozoa, GSH displayed maximal staining in the midpiece and tail regions. The highest levels of gamma-GT were encountered in the epididymis. The concentration of Glu was also high in the epididymis. Its formation may be due to the hydrolytic activity of gamma-GT, which, in addition, may have an important role in the transfer of Glu residues to reactive groups on the sperm surface.
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PMID:Glutathione, L-glutamic acid and gamma-glutamyl transpeptidase in the bull reproductive tissues. 289 39

During postnatal development, gamma-glutamyl transpeptidase (gamma-GT), reduced glutathione (GSH), and L-glutamic acid (L-Glu) were assayed in the epididymides of rats at 5-day intervals between 10 and 60 days of age and compared to adult levels. gamma-GT activity (with gamma-glutamyl-p-nitroanilide as substrate) and L-Glu (nicotinamide adenine dinucleotide conversion-dependent assay) were measured photometrically, while GSH (o-phthalaldehyde reaction) was quantified with a fluorometric assay. In immature rats, the epididymal gamma-GT was very low but increased after 25 days of age in the caput and after 50 days of age in the cauda. The enzyme level in the epididymal caput was by far the highest in the adult rat reproductive tissues. The postnatal increase of gamma-GT in epididymal caput and cauda was associated with a decline of its substrate GSH and an accumulation of the product L-Glu. These observations provide evidence for the in vivo hydrolytic activity of gamma-GT and explain the high levels of L-Glu found in the epididymis of rats and other mammals.
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PMID:Gamma-glutamyl transpeptidase, glutathione, and L-glutamic acid in the rat epididymis during postnatal development. 290 Jun 57

We have previously reported that endothelial cell (EC) xanthine dehydrogenase/xanthine oxidase (XD/XO) activity correlates inversely with the O2 tension to which the cells are exposed. Whether this effect is related to the production of reactive O2 species is unclear. We exposed bovine pulmonary artery EC to various conditions that altered the redox status of the cells: 1) hypoxia (3% O2) and normoxia (20% O2); 2) menadione (MEN), known to generate O2 radicals; 3) catalase (CAT) and reduced glutathione (GSH), which detoxify H2O2; and 4) various NO-generating systems. Changes in intracellular XO and XO + XD activities were correlated with rates of extracellular H2O2 release from the same cells. Conditions that decreased extracellular H2O2 release (hypoxia, CAT, and GSH) produced significant and parallel increases in intracellular XO and XO + XD activities in a time-dependent fashion. MEN treatment increased extracellular release of H2O2 and subsequently reduced intracellular XO and XO + XD activities. NO-generating agents did not change extracellular release of H2O2 but significantly reduced XO and XO + XD activities. The latter effect was prevented by reduced hemoglobin. Scavengers of hydroxyl radicals reversed the inhibition of XO and XO + XD activities produced by MEN but not that produced by NO. While NO significantly inhibited XD/XO activity from rat epididymal fat pad, it did not affect XD/XO mRNA expression in these cells. We conclude that intracellular XD/XO activity is sensitive to changes in oxidant-generating and protective systems. Inhibition of XD/XO activity by NO may be mediated through direct binding of NO to the enzyme iron-sulfur moiety or to its sulfhydryl groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of nitric oxide and cell redox status on the regulation of endothelial cell xanthine dehydrogenase. 776 82

In vitro maturation and in vitro fertilization techniques in pigs have progressed considerably in recent years. Many reports focus on the factors affecting in vitro maturation that lead to normal male pronuclear formation or monospermy after fertilization in vitro. It is suggested that pig follicular fluid (pFF), follicle somatic cells and various hormones are important factors for the maintenance of cytoplasmic maturation of oocytes in vitro, but that fetal calf serum (FCS), which is generally added to maturation medium, is detrimental. A series of experiments clearly indicate that the glutathione (GSH) content of matured oocytes increases greatly when maturation medium is supplemented with cysteine, a precursor of GSH, and the rates of male pronuclear formation increase in parallel with the increasing GSH content. To prevent polyspermy, conditions of maturation and of fertilization in vitro are important. Culture of oocytes in medium with FCS for the first 24 h and with BSA for the second 24 h decreases the incidence of polyspermy, without a significant effect on nuclear maturation. However, it has been shown that secretory macromolecules of the oviduct may reduce the incidence of polyspermy by interacting with fertilizing spermatozoa rather than with oocytes. A reduction of polyspermy by treating spermatozoa with pFF is also reported. In addition to the many improvements in the methodology of in vitro fertilization using unfrozen spermatozoa in pigs, techniques for fertilizing oocytes in vitro with frozen epididymal and ejaculated spermatozoa have also recently been developed.
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PMID:Effectiveness of in vitro maturation and in vitro fertilization techniques in pigs. 814 14

Glutathione S-transferases (GSTs) are a family of isozymes that catalyze the conjugation of glutathione (GSH), a tripeptide found in all mammalian cells; this function plays a protective role, as the addition of GSH to an electrophile generally forms a less toxic product. The pi class of GSTs contains homodimers of the Yf subunit, also known as Yp or rat subunit 7; this subunit is found in high concentrations in the testis and epididymis. The objective of the present study was to localize immunocytochemically the Yf subunit in the testis and in the various regions of the epididymis using light, electron, and confocal microscopy. In the testis, immunoperoxidase staining was localized exclusively to Sertoli and Leydig cells. The low cuboidal epithelial cells of the rete testis and the sparse ciliated cells of the ductuli efferents were also immunoreactive. A distinct pattern of immunostaining for the Yf subunit was observed in the different regions of the epididymis. The proximal area of the initial segment showed intense reactivity localized to epithelial basal cells. Basal cells in the middle area of the initial segment were also reactive, as were a second unidentified population of cells located in the apical region of the epithelium. The epithelium, including both principal and basal cells, in the distal initial segment, intermediate zone, and proximal caput epididymidis showed a weak, moderate, or strong degree of reactivity, respectively. In the distal caput epididymidis, however, principal cells showed a checkerboard-like pattern of immunoreactivity, with some cells being intensely stained or faintly stained, whereas others were unreactive. Strikingly, in the corpus and proximal cauda epididymidis, intense immunostaining was localized exclusively over the epithelial basal cells. As viewed in the light and confocal microscope, the intensely stained basal cells showed extensive processes that covered most of the base of the epididymal tubule. Upon quantitation of the immunogold labeling density (the number of gold particles/microns2) in principal and basal cells of the different regions of the epididymis, we observed a sharp decline in immunogold labeling of principal cells coupled with a dramatic increase in labeling of basal cells as we progressed along the tissue, particularly in the transition from the caput to the corpus epididymidis. This study constitutes the first demonstration of a protein that is selectively expressed in epithelial basal cells of the corpus and proximal cauda epididymidis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Immunocytochemical localization of the Yf subunit of glutathione S-transferase P shows regional variation in the staining of epithelial cells of the testis, efferent ducts, and epididymis of the male rat. 847 35


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