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

Mature rabbit spermatozoa from the cauda epididymidis suspended in potassium Tris phosphate buffer at 24 degrees C produced O2.-, as measured by reduction of acetylated ferricytochrome c, with an intrinsic rate of 0.20 nmol/min per 10(8) cells. This rate increased to 1.80 nmol/min per 10(8) cells in the presence of 10 mM cyanide. These spermatozoa contain 2.8 units per 10(8) cells of superoxide dismutase activity, 95% of which is sensitive, and 5% of which is insensitive, to cyanide inhibition. These activities correspond to the cytosolic Cu-Zn form and the mitochondrial Mn form of the dismutase, respectively. Only the cyanide-sensitive form is released from the sperm on hypo-osmotic treatment or sonication. Hypo-osmotically treated rabbit epididymal spermatozoa produced O2.- with an intrinsic rate of 0.24 nmol/min per 10(8) cells, which increased to 0.58 nmol/min per 10(8) cells in the presence of 10 mM cyanide. Both intact and hypo-osmotically treated cells react with O2.- in a second order reaction as inferred from the hyperbolic dependence on cell concentration of O2.- production rate in both the absence and presence of cyanide. The second order rate constant for this reaction with intact cells, kS, was calculated to be 22.9 X 10(-8) (cells/ml)-1 min-1 in its absence. For hypo-osmotically treated cells, the values of kS were 10.8 X 10(-8) (cells/ml)-1 min-1 and 8.2 X 10(-8) (cells/ml) -1 min-1, respectively. Since hypo-osmotically treated cells have lost much of their plasma membrane, the lower value of kS for the treated cells implies that this membrane is one site of reaction of O2.- with the cells. The increase in kS in the presence of cyanide, which inhibits superoxide dismutase and so increases O2.- production, suggests that the cells become more reactive with O2.- as its production rate increase, as would be expected for the occurrence of radical chain oxidation. This in turn suggests that superoxide dismutase plays a major role in protecting rabbit sperm against damage from lipid peroxidation.
 ...
PMID:Production of superoxide and activity of superoxide dismutase in rabbit epididymal spermatozoa. 629 28

1. The acute effect of hexachlorocyclohexane (HCH) administration (i.p.) on testicular antioxidant system and lipid peroxidation (LPX) in immature and mature rats (15- and 90-day-old, respectively) were compared. 2. In both the age groups, the level of LPX in crude homogenate of testis (endogenous, as well as FeSO4, and ascorbic acid-stimulated) was increased after 6 hr of HCH treatment and remained high till 24 hr. However, FeSO4 and ascorbic acid-stimulated LPX was higher in 90-day-old rats in comparison to 15-day-old rats. HCH treatment also resulted in elevation of LPX level in testicular subcellular (nuclear, mitochondrial and microsomal) fractions by 6 hr of treatment. However, the magnitude of increase was greater in case of 90-day-old rats. 3. Activities of testicular cytosolic superoxide dismutases (total and CN(-)-resistant) of rats of 15- and 90-day-old age groups decreased significantly after 6 hr of HCH treatment, and remained decreased till 24 hr of the pesticide treatment. The percentage of decrease was higher in 15-day-old rats than 90-day-old rats. CN(-)-sensitive SOD activity of testis was found to decrease by 12 and 24 hr after the pesticide treatment in 15- and 90-day-old rats, respectively. The activity of catalase decreased 6 hr after the pesticide treatment in both the age groups. However, the magnitude of decrease was similar for both age groups of rats. 4. Testicular glutathione content, as well as levels of glutathione metabolizing enzymes (glutathione peroxidase and glutathione reductase), did not change in response to HCH treatment, whereas ascorbic acid content decreased by 12 and 6 hr after HCH treatment in 15- and 90-day-old rats, respectively. The level of H2O2 was found to be elevated after 6 hr of the pesticide treatment in both age groups. 5. Total epididymal sperm number was comparable in all experimental groups. However, the percentage of dead and damaged spermatozoa was significantly enhanced in HCH treated rats. 6. Acute HCH administration to rats results in induction of oxidative stress in the testis which depends upon the age of the animal.
 ...
PMID:Comparison of hexachlorocyclohexane-induced oxidative stress in the testis of immature and adult rats. 946 84

Mammalian caput and cauda epididymidal spermatozoa exhibit diverse stages of maturation, and their plasma membrane shows diverse composition and stability levels, thus enabling these spermatozoa to undergo the acrosomal reaction after transit through the epididymis. As a result, the study of antiperoxidative mechanisms is quite relevant, since epididymal spermatozoa must be properly protected against agents such as reactive oxygen species, which can impair the complex maturation process. We considered activities of certain enzymes (glutathione peroxidase [GPx], phospholipid hydroperoxide glutathione peroxidase [PHGPx], glutathione reductase [GR], superoxide dismutase [SOD], and catalase [CAT]) and the vitamin E content in isolated rat caput and cauda epididymidal spermatozoa. The results indicate that caput epididymidal sperm have significantly greater PHGPx (3.5x), GPx (2.4x), and SOD (1.7x) activities, as well as a greater amount of vitamin E (3.8x). There were no detectable differences in the GR and CAT activities of caput and cauda epididymidal spermatozoa. The substantial drop in PHGPx activity during epididymal transit is discussed in relation to an additional function of this enzyme: the use of caput sperm protamines as a sulfhydryl substrate. In vitro peroxidation of the two sperm populations by the free radical generator (azo-initiator) 2,2'-azobis(2-amidinopropane) dihydrochloride revealed that only about 13% of the vitamin E content of the caput epididymidal spermatozoa was consumed, which contrasts with the greater consumption (about 70%) of the vitamin in cauda epididymidal spermatozoa. Selective inhibition of PHGPx, SOD, or CAT did not change this picture. The higher susceptibility of cauda epididymidal spermatozoa to radicals is discussed in relation to the diverse enzymatic activities, vitamin E content, and peroxidative response. These factors are correlated with the different stages of sperm cell maturation, which are characterized-from caput to cauda epididymidis-by progressive destabilization of the plasma and acrosomal membranes.
 ...
PMID:Antioxidant systems in rat epididymal spermatozoa. 974 22

Effect of repeated oral administration of hexachlorocyclohexane (HCH; 10 and 20 mg/kg body weight per day for 7, 15 and 30 days) on antioxidant defence system and lipid peroxidation (LPX) in the testis was compared between immature (15-day-old) and mature (90-day-old) rats. In both age-groups of rats, the pesticide elicited a significant decrease in the activities of cytosolic superoxide dismutase (SOD; total and CN(-)-resistant) and catalase, and ascorbic acid content together with an increase in the levels of LPX (both in crude homogenate and subcellular fractions) and H2O2. Testicular glutathione peroxidase (GPx; total and non-selenium-dependent) activity was enhanced in both the age-groups of rats while the testicular glutathione content as well as glutathione reductase activity remained unaltered. HCH treatment resulted in a decrease of total epididymal sperm number with a higher incidence of dead and damaged spermatozoa, and sperms having anomalous head. Statistical analyses suggest that the alterations in the testicular antioxidant defence profile in the rat are not only dependent on the duration of pesticide treatment, but also influenced by age.
 ...
PMID:Age-related changes in rat testicular oxidative stress parameters by hexachlorocyclohexane. 1035 Jan 90

The aim of this study was to investigate whether the dog sperm acrosome reaction can be induced by progesterone and whether the action of progesterone is mediated by binding of progesterone to a receptor on the sperm plasma. Progesterone-BSA conjugate labeled with fluorescein isothiocyanate (P-BSA-FITC) in combination with a vital stain, ethidium homodimer, was applied to visualize the presence of the progesterone receptor on living spermatozoa. Ten mM progesterone increased the acrosome reaction in viable spermatozoa over time from 3 +/- 1% at 0 hours to 69 +/- 8% at 6 hours (six dogs). In freshly ejaculated sperm from six dogs, P-BSA-FITC staining was observed in 13 +/- 1% of the viable, acrosome-intact cells, as characterized by bright fluorescence over the entire apical region. The proportion of P-BSA-FITC-stained, viable, acrosome-intact cells increased to 84 +/- 11% following 7 hours incubation in a low-calcium medium. In contrast, the majority (72 +/- 3%) of fresh epididymal sperm already demonstrated bright P-BSA-FITC staining. Apparently, epididymal spermatozoa already possess the progesterone receptor. The receptor is masked at ejaculation and subsequently gradually exposed.
 ...
PMID:Acrosome reaction in dog sperm is induced by a membrane-localized progesterone receptor. 1045 98

Intraperitoneal leptin administration to wild-type and ob/ob mice caused a prompt activation of Stat1 and Stat3, the former to a lesser extent, in epididymal adipose tissue. Immunoblot experiments showed that tyrosine phosphorylation of Stat3 increased in total cellular extracts and that the phosphorylated protein translocated into the nucleus upon leptin treatment. Tyrosine phosphorylation and nuclear translocation of Stat1 were evident only in ob/ob mice. Gel shift and supershift analyses showed that leptin activated sis-inducible element (SIE) binding activity of adipose nuclear extracts, with Stat3 homodimer as the predominant complex. Stat1/3 heterodimers and Stat1 homodimers take part as well in the response in wild-type and ob/ob mice, although to a lesser degree. AP-1 binding activity was also induced in adipose tissue by in vivo leptin treatment with a time course that suggests a post-transcriptional inductive mechanism. This effect was greater in the ob/ob than in wild-type mice. Our data indicate that leptin operates in vivo directly on adipose tissue by triggering responses that modulate gene expression.
 ...
PMID:Leptin activates Stat3, Stat1 and AP-1 in mouse adipose tissue. 1106 48

The plasma membrane of spermatozoa undergoes substantial remodeling during passage through the epididymal duct, principally because of changes in phospholipid composition, exchange of glycoproteins with epididymal fluid, and processing of existing membrane proteins. Here, we describe the interaction of an epididymal glycoprotein recognized by monoclonal antibody 2D6 with the plasma membrane of rat spermatozoa. Our goals have been to understand more about the mechanism of secretion of epididymal glycoproteins, how they interact with the sperm's plasma membrane, and their disposition within it. Reactivity to 2D6 monoclonal antibody was first detectable in principal cells in the distal caput epididymidis and as a soluble high-molecular-weight complex in the secreted fluid. It was not associated with membranous vesicles in the duct lumen. On cauda spermatozoa 2D6 monoclonal antibody recognized a 24-kDa glycoprotein (the subunit of a disulfide cross-linked homodimer of 48 kDa) that was present on the plasma membrane overlying the sperm tail. Binding of 2D6 to immature spermatozoa in vitro was cell-type specific but not species specific, and the antigen could only be extracted from cauda spermatozoa with detergents. Sequencing studies revealed that the 24-kDa glycoprotein was a member of the beta-defensin superfamily of small pore-forming glycopeptides of which several others (ESP13.2, Bin1b, E-2, EP2, HE2) are found in the epididymis. This evidence suggests that some epididymal glycoproteins are secreted into the luminal fluid in a soluble form and bind to specific regions of the sperm's surface via hydrophobic interactions. Given the antimicrobial function of beta-defensins, they have a putative role in protecting spermatozoa and the epididymis from bacterial infections.
 ...
PMID:Secreted epididymal glycoprotein 2D6 that binds to the sperm's plasma membrane is a member of the beta-defensin superfamily of pore-forming glycopeptides. 1289 Jul 30

The aim of this study was to investigate the antioxidant role of zinc (Zn) in the Cd-exposed testes of Wistar rats. Subchronic exposure to Cd (CdCl(2), 40 mg/l, per os) for 30 days resulted in a significant reduction in growth rate (-11%) and relative weights of testes (-36%) and seminal vesicles (-80%). Treated rats displayed a decrease in testicular and plasma testosterone levels, respectively (-70%, P<0.05; -48%, P<0.05), epididymal sperm count (-22%, P<0.05), and spermatozoa motility (-35%, P<0.05). In contrast, Cd increased the malondialdehyde (+46%, P<0.05), metallothionein (+200%, P<0.05), and 8-oxodGuo concentrations (+71%, P<0.05) in the testis. In the gonad, Cd decreased the GPx (-30%, P<0.05), CAT (-32%, P<0.05), mitochondrial Mn-SOD (-34%, P<0.05), and cytosolic CuZn-SOD (-32%, P<0.05) activities. Zinc supplementation (ZnCl(2), 40 mg/l, per os) in the Cd-exposed rats restored the activities of GPx, CuZn-SOD, and Mn-SOD in the testes to the levels of the control group. Moreover, zinc administration was capable of reducing the elevated levels of malondialdehyde in the testis. Interestingly, zinc supplementation attenuated DNA oxidation induced by Cd in the gonad and restored the testosterone level and sperm count to the levels of the control group. Zinc administration minimized oxidative damage and reversed the impairment of spermatogenesis and testosterone production induced by Cd in the rat testis.
 ...
PMID:Preventive effect of zinc against cadmium-induced oxidative stress in the rat testis. 1742 Jun 18

We studied the immunoexpression of Cu/Zn superoxide dismutase (Cu/ZnSOD) and mRNAs expression of extracellular superoxide dismutase (E-SOD), and epididymal specific glutathione peroxidase 5 (GPX5), in epithelial cells of caput and cauda epididymis of rats treated with finasteride, a steroid-based inhibitor of 5alpha-reductase. The 5alpha-reductase is known to exist in two isoforms. Both 5alpha-red1 and 5alpha-red2 catalyse the irreversible conversion of T into DHT. Formation of DHT in the epididymis is mostly due to the action of 5alpha-red2 and finasteride is more potent inhibitor of this isoform. Rats were treated with finasteride for 56 days covering the duration of one spermatogenesis (four cycles of the seminiferous epithelium). Although E-SOD mRNA is normally expressed in cells of cauda but not of caput epididymis, treatment with finasteride produced the E-SOD transcript in cells of caput epididymis too. The GPX5 transcript was detected in cells of caput epididymis of control and experimental rats, but the level of expression measured densitometrically was significantly lower in finasteride-treated rats. The immunoexpression of Cu/ZnSOD was also changed in epididymis of finasteride-treated rats. Finasteride appears to change the pattern of expression of antioxidant enzymes and may alter the protective function of the epididymis in relation to spermatozoa.
 ...
PMID:Expression of E-SOD, GPX5 mRNAs and immunoexpression of Cu/ZnSOD in epididymal epithelial cells of finasteride-treated rats. 1881 21

Aroclor 1254 (A1254) has been shown to have potential testicular toxicity. The mechanism of action of A1254 on male reproduction is not clear. The present study was designed to investigate the potential toxicity of A1254 on rat spermatogenesis. Oxidative stress was also assessed in testicular mitochondria as an underlying mechanism. Adult male Wistar rats were injected with A1254 (0, 0.75, 1.5 or 3mg/kg/day i.p.) or with vehicle (corn oil) for 20 consecutive days. A1254 at doses of 1.5 and 3mg/kg/day resulted in a significant decrease in body weight, testes weight, epididymal and relative epididymal weight. Similarly, the relative testis weight was significantly decreased at 3mg/kg/day. Sperm count, motility and daily sperm production were significantly decreased at 1.5 and 3mg/kg/day. The same two doses significantly inhibited the activities of testicular mitochondrial CAT, GPx and GR while the activity of SOD was significantly decreased by 0.75, 1.5 and 3mg/kg/day. The levels of H(2)O(2) generation and LPO were significantly increased in mitochondria in a dose-related pattern. GSH and Vit C were significantly decreased at 0.75, 1.5 and 3mg/kg/day. In conclusion, A1254 impairs spermatogenesis as evidenced, at least partly, by induction of oxidative stress in testicular mitochondria.
 ...
PMID:Aroclor 1254 impairs spermatogenesis and induces oxidative stress in rat testicular mitochondria. 1930 9


1 2 3 4 Next >>