Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treating bovine epididymal spermatozoa with rutamycin or rotenone inhibited both respiration and motility supported by endogenous substrates. When oxidative phosphorylation had been blocked with various inhibitors, pyruvate was metabolized to yield ATP and restored motility. Fructose, which is metabolized via glycolysis to yield ATP, was also able to resuscitate the cells. Other substrates tested (lactate, acetate, alpha-ketoglutarate, or glyoxylate) were unable to restore motility in rutamycin-treated cells. In the presence of pyruvate, the phosphorylation uncoupler, carbonylcyanide-p-trifluoromethyoxphenylhydrazone, reduced motility and ATP to common levels in untreated cells or cells treated with rutamycin or rotenone. Pyruvate is thus metabolized to produce ATP by a pathway independent of oxidative phosphorylation associated with the electron transport chain. 5-Methoxyindole-2-carboxylic acid, an inhibitor of lipoyldehydrogenase, prevented the increase of motility and ATP in rutamycin-treated cells, indicating that alpha-keto acid oxidation is involved in the production of ATP from pyruvate when rutamycin is present. With pyruvate present, bongkrekic acid, antimycin A, and anaerobiosis eliminated motility, reduced ATP to low levels, and also significantly reduced the rate of pyruvate metabolism. Acetate was produced from pyruvate only when cellular ATP concentrations were low. Decreases in free carnitine concentrations showed that pyruvate initially used was converted to acetylcarnitine. The results indicate that the intramitochondrial lactate dehydrogenase X, which is unique to spermatozoa, allows the NADH resulting from pyruvate oxidation to reduce other pyruvate molecules to lactate. Pyruvate thus competes with, and can substitute for, the NADH dehydrogenase of the electron transport chain. Pyruvate rapidly repletes the acetylcarnitine pool under a variety of conditions.
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PMID:Pyruvate metabolism in bovine epididymal spermatozoa. 83 18

Inheritance of the mitochondrial genome is known to be exclusively maternal. To determine whether the loss of paternal mitochondria could be due to a deficiency of RNA in the spermatozoal mitochondria, the expression of mitochondrial genes was studied in testicular cells at various stages of spermatogenesis and in epididymal spermatozoa. The presence of mitochondrial transcripts was examined by Northern blot analysis using probes for the following mitochondrially encoded genes: 12 S and 16 S ribosomal RNAs and a group of mRNAs including cytochrome oxidase subunits I and II (COI-COII), cytochrome b (cyt b), adenosine triphosphatase (ATPase) subunits 6 and 8, and subunit 1 of the respiratory chain NADH dehydrogenase (ND1). Comparison of total testicular RNA preparations from prepuberal (6, 8, 12, 16, 18, 20, 22, and 30 days old) and sexually mature (45 days old) mice revealed no major qualitative or quantitative differences in the levels of the mitochondrial transcripts described above. Similar results were observed from enriched preparations of type A and B spermatogonia and interstitial cells obtained from the testes of 8-day-old mice. Transcripts for COI-COII, ATPase 6, or ND1 were reduced in amount in the enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies when compared to the amount in total testis or liver RNA. Transcripts of all the mitochondrial genes analyzed were present in RNA preparations isolated from sperm midpiece tails obtained after sonication of epididymal spermatozoa. These studies demonstrate that (a) during testicular development the levels of mitochondrial RNA in total testicular extracts show no major qualitative and quantitative differences; (b) the mitochondrial transcripts in enriched populations of type A and type B spermatogonia are not different from those obtained from total testes extracts; (c) mitochondrial transcript levels gradually decrease in enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies; and (d) the mitochondrial rRNAs and mRNAs encoded by several mitochondrial genes can be isolated from sperm midpiece tails.
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PMID:Mitochondrial gene expression in male germ cells of the mouse. 277 68

A rapid decrease in male fertility in laboratory animals exposed to 1,2-dibromo-3-chloropropane (DBCP) has been suggested to be due, in part, to a postglycolytic inhibition of sperm carbohydrate metabolism. The present studies were performed to identify the specific site of DBCP-induced inhibition of intermediary metabolism. 14CO2 generation by epididymal sperm, isolated from Fischer 344 rats, was measured using radiolabeled tricarboxylic acid (TCA) cycle intermediates: acetyl CoA, citrate, alpha-ketoglutarate, and succinate. There was 0-28% inhibition of CO2 generation after addition of 0.5 mM DBCP and 81-98% inhibition with 3 mM DBCP, with all four substrates. The activities of alpha-ketoglutarate dehydrogenase, pyruvate dehydrogenase, malate dehydrogenase, and lactate dehydrogenase were not inhibited by DBCP. Since the DBCP-induced inhibition of metabolism of different substrates to CO2 was similar, and since DBCP did not inhibit enzyme activities of glycolysis or the TCA cycle, a common site of inhibition was suspected. In evaluations of mitochondrial electron transport chain activity, DBCP (3 mM) inhibited oxygen consumption resulting from metabolism of endogenous substrates plus alpha-ketoglutarate or malate by about 80%. When succinate, an FAD-dependent oxidation, was used as a substrate, oxygen consumption was not inhibited by DBCP. It is concluded that DBCP inhibits sperm carbohydrate metabolism at the NADH dehydrogenase step in the mitochondrial electron transport chain.
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PMID:A biochemical basis for 1,2-dibromo-3-chloropropane-induced male infertility: inhibition of sperm mitochondrial electron transport activity. 367 26

The activities of alkaline phosphatase and reduced nicotinamide adenine dinucleotide (NADH) diaphorase in the principal cells of the guinea pig epididymis were studied histochemically. Alkaline phosphatase activity was absent from the principal cells but was present in the basement membrane of the epididymal epithelium. NADH diaphorase activity was distributed throughout the cytoplasm of the principal cells in each epididymal segment. There was a gradual increase in NADH diaphorase activity from segments 1 through 7. Possible functions of alkaline phosphatase and NADH diaphorase in the epididymis are discussed.
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PMID:Localization of alkaline phosphatase and NADH diaphorase in the principal cells of the guinea pig epididymis. 668 19

The triazine dyes, Cibacron blue F3GA and Procion red HE3B inhibited diaphorase activity of ferredoxin-NADP+ reductase, in a competitive manner with respect to NADPH. The Ki values were 1.5 and 0.2 microM, respectively. Binding of the dyes to the flavoprotein, as measured by difference spectroscopy, indicated an apparent stoichiometry of 1 mol dye/mol reductase and was prevented by NADP+ or high ionic strength. Chemical modification of a lysine residue and a carboxyl group at the NADP(H) binding site of the enzyme prevented complex formation with Procion red. Procion red showed a higher affinity for ferredoxin-NADP+ reductase than Cibacron blue. The Kd values were 1.9 and 5 microM, respectively. Once covalently linked to a Sepharose matrix, the triazine compounds specifically bind the flavoprotein. The interaction is partially electrostatic and partially hydrophobic. The enzyme can be eluted by high concentrations of salt or low concentrations of the corresponding coenzyme. The use of this affinity column allows the rapid purification of ferredoxin-NADP+ oxidoreductase from spinach leaves with good yields.
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PMID:Interaction of ferredoxin-NADP+ oxidoreductase with triazine dyes. A rapid purification method by affinity chromatography. 682 90

Histochemical studies have been made of the isocitrate dehydrogenase, succinic dehydrogenase, malate dehydrogenase, glutamate dehydrogenase, DPN diaphorase, TPN diaphorase, delta 5-3 beta-hydroxysteroid dehydrogenase and monoamine oxidase in the caput, corpus and cauda epididymides of normal and alpha chlorohydrin (6.5 mg/kg/9 days) treated rats. Administration of alpha chlorohydrin in a low dose caused a conspicuous decrease in all these enzymes except delta 5-3 beta-HSD, in various cell types of epididymal epithelium and sperms. Biochemical estimations of isocitrate dehydrogenase, succinic dehydrogenase, malate dehydrogenase and delta 5-3 beta-HSD have further supported and confirmed these histochemical observations. These changes in enzyme activities after treatment with low dose of alpha chlorohydrin strongly suggest that TCA cycle and amino acid metabolism of epididymis become defective, much earlier before any histological damage to the epididymis becomes visible.
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PMID:Effects of low doses of alpha chlorohydrin on the dehydrogenases and oxidases of rat epididymal epithelium and sperms: a correlative histochemical and biochemical study. 694 44

The glucose transport mechanism of rat epididymal fat cells was reconstituted into egg lecithin liposomes, and their carrier-mediated transport activity ws estimated from the difference in the rates of uptake of D-[3H]glucose and L-[14C]glucose. Insulin increased the glucose transport activity in the plasma membrane-rich fraction while decreasing the activity in the Golgi-rich fraction in agreement with our previous data (Suzuki, K., and Kono, T. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 2542-2545). The development of the insulin effects was inhibited when cells were exposed to 2,4-dinitrophenol or KCN before the insulin treatment. In addition, the reversal of the insulin effects was blocked upon exposure of insulin-treated cells to 2,4-dinitrophenol or KCN prior to the elimination of the hormone. In contrast, neither development nor reversal of the insulin effects was affected by cycloheximide or puromycin. The temperature coefficients of the transport activities reconstituted from the basal or insulin-treated forms of the plasma membrane-rich or Golgi-rich fractions were all identical. The recoveries of protein, 5'-nucleotidase, UDP-galactose:N-acetylglucosamine galactosyltransferase, and NADH dehydrogenase into subcellular fractions were determined. However, net effects of insulin on the glucose transport activities have remained unknown for lack of an appropriate marker enzyme of the Golgi-like vesicles associated with the transport activity. It is suggested that the glucose transport mechanism is recycled between the plasma membrane-rich and Golgi-rich fractions by an energy-dependent reaction.
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PMID:Energy-dependent and protein synthesis-independent recycling of the insulin-sensitive glucose transport mechanism in fat cells. 701 68

Recent work has implicated nitric oxide (NO) in several aspects of male genital physiology including erectile function and androgen secretion, as well as in vitro effects on sperm motility and capacitation. The objectives of this study were to characterize the distribution of endothelial nitric oxide synthase (eNOS) in "normal" human testis, epididymis, and vas deferens and in testis pathology. Nitric oxide synthase protein was localized immunohistochemically using an eNOS monoclonal antibody. Endothelial NOS protein co-localized to areas that showed positive NADPH diaphorase activity. Within the testis, eNOS protein was localized to the cytoplasm of Leydig cells and Sertoli cells at all stages of spermatogenesis. Within the epididymis and vas deferens, eNOS was localized to the epithelium. Endothelial NOS was also localized to endothelial cells in all tissues; it was not detectable in normal germ cells. Endothelial NOS and diaphorase activity were, however, detected in degenerating or apoptotic intraepithelial germ cells. In addition, prematurely shed spermatocytes and spermatids had intense eNOS expression. Previous studies have suggested a role for NOS in the contractile, hemodynamic, and hormonal aspects of testicular function as well as in epididymal secretion. The studies reported herein suggest a role for eNOS in spermatogenesis and germ cell degeneration.
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PMID:Immunohistochemical localization of endothelial nitric oxide synthase in human testis, epididymis, and vas deferens suggests a possible role for nitric oxide in spermatogenesis, sperm maturation, and programmed cell death. 890 2

Functionally immature spermatozoa leave the testis mature during epididymal transit. This process of maturation involves either addition of new proteins or modification of existing proteins onto the sperm domains that are responsible for domain-specific functions. Epididymal proteins are preferred targets for immunocontraception. In an attempt to identify epididymis-specific sperm proteins, we used a novel combinatorial approach comprising subtractive immunization (SI) followed by proteomics. Following SI, sera of mice were used for immunoproteomics, which led to the identification of 30 proteins, of which four proteins namely sperm head protein 1, sperm flagella protein 2 (SFP2), SFP3, and SFP4 are being reported for the first time on sperm. Another group of four proteins namely collagen alpha-2 (I) chain precursor, homeodomain-interacting protein kinase 1, GTP-binding protein Rab1, and ubiquinol cytochrome c reductase core protein II although reported earlier in testis are being reported for the first time in epididymal sperm. Furthermore, seven out of these eight novel proteins could be validated using peptide ELISA. These data are a useful repository, which could be exploited to develop targets for post-testicular immunocontraception or biomarkers for infertility diagnosis and management.
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PMID:Identification of novel immunodominant epididymal sperm proteins using combinatorial approach. 1942 63

In this work, two groups of Wistar rats were fed ad libitum, one with standard chow (22% protein) and the other with hypoproteic chow (8% protein), from the 210th to the 345th day of life. Compared to the animals fed with standard chow, the animals fed with hypoproteic chow exhibited hypophagia (ingestion about 30% lower), mean weight gain 4.46% lower, greater amount of retroperitoneal and peri-epididymal fat (19% on average), lower Lee index, decrease of total plasma proteins and plasma globulins and maintenance of plasma albumin. The quantitative and morphometric analysis of the NADH-diaphorase positive myenteric neurons yielded a larger number of small neurons and a smaller number of medium neurons in the animals subjected to the hypoproteic chow, demonstrating that the neuronal growth was affected by the diet. In the animals fed with hypoproteic chow, a 20% decrease in the NADH-diaphorase positive neurons of the forestomach and a 10% decrease in those of the glandular stomach were observed.
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PMID:Morphometric and quantitative study of the myenteric neurons of the stomach of malnourished aging rats. 1962 41


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