Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mature boar spermatozoa oxidized glycerol to carbon dioxide in the absence of any detectable activity of glycerol kinase. With triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase inhibited by the presence of 3-chloro-1-hydroxypropanone (CHOP), dihydroxyacetone phosphate accumulated in incubates when glycerol-3-phosphate was the substrate, but not when it was glycerol. Both dihydroxyacetone and glyceraldehyde could be used as substrates; in the presence of CHOP, dihydroxyacetone phosphate and fructose-1,6-bisphosphate accumulated when dihydroxyacetone was the substrate, but not when it was glyceraldehyde. The metabolic pathways glycerol----glyceraldehyde----glyceraldehyde 3-phosphate and dihydroxyacetone----dihydroxyacetone phosphate have been shown to operate in these cells.
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PMID:Metabolism of glycerol by mature boar spermatozoa. 155 74

Modern research in male contraception is focusing on 4 areas: 1) hormonal control of spermatogenesis, the complex processes of spermiogenesis in the testis where the spermatogonia stem cells mitotically divide into spermatocytes, which meiotically divide into nondividing spermatids, which become the spermatozoa; 2) direct (nonhormonal) inhibition of spermatogenesis; 3) the suppression of sperm maturation in the epididymis; and 4) the immunological suppression of fertility through the identification of an antisperm antibody. Hormonal suppression of spermatogenesis requires depression of testosterone levels in the testis, either by direct inhibition of the Leydig cells or by inhibition of the hypothalamic production of luteinizing hormone-releasing hormone, which induces the pituitary secretion of luteinizing hormone, which induces the secretion of testosterone. Testosterone suppression in the testis must be accompanied by exogenous androgen supplements or there will be loss of libido and potency. Preparations under investigation in the hormonal suppression of spermatogenesis include monthly injections of 200 mg depot medroxyprogesterone acetate with 200 mg testosterone enanthate; danazol with testosterone enanthate; anabolic steroids, such as 19-NT-hydroxyphenylpropionate; cyproterone acetate, an antiandrogen with progestational effects; and luteinizing hormone-releasing hormone agonists, which down-regulate pituitary receptors, or luteinizing hormone-releasing hormone antagonists, which competitively block receptor activation. None of these preparations have yet struck a balance where they can completely but reversibly block spermatogenesis at doses which do not have toxic or feminizing effects. 3 nonhormonal agents which suppress sperm production are gossypol, extract of Trypterigium wilfordii, and tolnidamine. Gossypol, an extract of cottonseed oil, has been widely studied in China and has been found 99% effective in producing azoospermia or severe oligospermia. However, it is extremely toxic, damages cells in the seminiferous epithelium, and causes hypokalemia. Over time, its effects become irreversible, and its mutagenicity and teratogenicity are not known. Agents which suppress sperm maturation in the epididymis act after cell division is complete and hence are not mutagenic, but they are extremely toxic. Alpha-chlorohydrin and 6-chloro-6 deoxysugars act by inhibiting the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase with the result that sperm cannot metabolize sugar. The sulfonamide compound, sulfasalazine, disrupts sperm motility by a mechanism not yet known. The development of a contraceptive vaccine relies on the identification of the antigenic determinants on sperm surface. Even if such a vaccine could be developed, there remains the problem of reversibility. None of the methods now being studied have demonstrated that they can reliably prevent unwanted pregnancy, and none have been around long enough for their longterm side effects to be known.
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PMID:Male contraception: current status and future prospects. 307 64

When boar spermatozoa were incubated with the (S)-isomer of the male antifertility agent alpha-chlorohydrin the activity of glyceraldehyde-3-phosphate dehydrogenase was inhibited. The (R)-isomer had no significant effect on the activity of this enzyme whereas (R,S)-3-chlorolactaldehyde caused an inhibition of its activity and also in that of lactate dehydrogenase. The in vitro production of (S)-3-chlorolactaldehyde, the active metabolite of (S)-alpha-chlorohydrin, was attempted by incubating boar spermatozoa with 1-chloro-3-hydroxypropanone. Preliminary results lead us to propose that this compound is converted into (S)-3-chlorolactaldehyde as well as to another metabolite which is an inhibitor of other enzymes within the fructolytic pathway.
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PMID:Inhibition of fructolytic enzymes in boar spermatozoa by (S)-alpha-chlorohydrin and 1-chloro-3-hydroxypropanone. 359 19

When ejaculated ram spermatozoa were incubated with (S)-alpha-chlorohydrin (up to 0.25 mM) the oxidative metabolism of fructose to carbon dioxide was inhibited in a concentration-dependent manner. This appears to be due to inhibition of glyceraldehyde-3-phosphate dehydrogenase which leads to the accumulation of fructose-1,6-bisphosphate, dihydroxyacetone phosphate and, to a lesser extent, glyceraldehyde-3-phosphate. (R)-alpha-Chlorohydrin (10 mM) had no significant effect on the oxidative metabolism of fructose. The inhibition of the oxidative metabolism of fructose by (S)-alpha-chlorohydrin (0.1 mM) was not immediate but was detected after incubation for 15 min. By contrast, (R,S)-3-chlorolactaldehyde (5 mM) caused an immediate inhibition of this metabolic pathway. 1-Chloro-3-hydroxyacetone (0.5 mM) immediately decreased the oxidative metabolism of fructose which resulted in the accumulation of key fructolytic intermediates in a manner comparable to that produced by (S)-alpha-chlorohydrin. At a concentration of 20 mM, 6-chloro-6-deoxyglucose had no significant effect on the metabolic activity of ram spermatozoa. We suggest that the anti-fructolytic actions of (S)-alpha-chlorohydrin and 1-chloro-3-hydroxyacetone are mediated via a common metabolite, (S)-3-chlorolactaldehyde, and that the inactivity of 6-chloro-6-deoxyglucose is due to the inability of ram spermatozoa to metabolise this chlorinated sugar to (S)-3-chlorolactaldehyde.
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PMID:Mechanism of inhibition of fructolysis in ram spermatozoa by chlorinated antifertility agents. 379 96

Damage to the plasma membrane of rabbit epididymal spermatozoa during spontaneous lipid peroxidation was examined by means of trypan blue uptake and expression of activity of the intracellular enzymes, lactate dehydrogenase and pyruvate kinase. Both the dye uptake and the expression of enzyme activity probe cell damage from lipid peroxidation as loss of integrity of the plasma membrane. A linear correlation was obtained between trypan blue staining of the cells and malondialdehyde production, a quantifiable measure of the extent of lipid peroxidation. At the point of trypan blue staining of all cells, 0.5 nmol malondialdehyde/10(8) cells was produced. This is the same amount produced at the point of complete loss of motility and superoxide dismutase activity. We have defined this as the "lipoperoxidative lethal end point." Expression of lactate dehydrogenase and pyruvate kinase activities increased with time of aerobic incubation. In the high Na+ medium, NTP, in which lipid peroxidation is slow, there is a linear correlation between increase in expressed enzyme activities and malondialdehyde production. But in the high K+ medium, KTP, in which lipid peroxidation is rapid, there is an initial rapid rise in expressed enzyme activity over 3 h, followed by a slower increase. Activities of rabbit sperm lactate dehydrogenase, pyruvate kinase, and flagellar ATPase were unaffected by aerobic incubations for up to 48 h, double the incubation period used for the assay of enzymatic activities for the first two. The activity of glyceraldehyde-3-phosphate dehydrogenase decreased during aerobic incubation, the time course matching the loss of motility. The subcellular distribution of lactate dehydrogenase in rabbit spermatozoa was determined: 4% in the mitochondrial matrix, 10% in the plasma membrane and 85% in the cytosolic compartment.
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PMID:Assessment of cell damage caused by spontaneous lipid peroxidation in rabbit spermatozoa. 623 Oct 58

Assay of maximal activities of 11 glycolytic enzymes in cell-free buffalo sperm extracts showed that hexokinase, phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase had the lowest activities, suggesting regulation of fructolysis at steps catalysed by these enzymes. The ratios of glyceraldehyde-3-phosphate dehydrogenase/phosphofructokinase (0.67) and phosphoglycerate kinase/phosphofructokinase (4.60) are typical of cells exhibiting high Pasteur effect (50% for ejaculated buffalo spermatozoa). The regulatory nature of phosphofructokinase was shown through its modulation by ATP, AMP and inorganic phosphate. The determination of fructolytic intermediates and cofactors and calculation of mass action ratios for each enzymic step revealed that hexokinase, phosphofructokinase, fructose-biphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase catalysed reactions far removed from the equilibrium. A regulatory role by glyceraldehyde-3-phosphate dehydrogenase appeared to be most likely because triosephosphates and inorganic phosphate accumulated more under anaerobic than under aerobic conditions.
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PMID:REgulation of glycolysis/fructolysis in buffalo spermatozoa. 645 53

It was confirmed that, under anaerobic conditions, fowl spermatozoa formed lactate from glucose thirteen times faster than turkey spermatozoa. The profiles of glycolytic enzyme activities were similar for spermatozoa from both species; however fowl spermatozoal activities were generally 2- to 4-fold higher. Exceptions were glycerophosphate mutase and lactate dehydrogenase activities which were respectively 9.5 and 41 times greater in fowl spermatozoa. In both species, spermatozoal glyceraldehyde-3-phosphate dehydrogenase had the lowest activity of the glycolytic enzymes.
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PMID:Glycolytic enzymes of fowl and turkey spermatozoa. 650 33

Male rats given 6-chloro-6-deoxyglucose (240 mg/kg/day for 28 days) developed spermatocoeles in their ductuli efferentes or caput epididymides. They had a lower serum triglyceride content than controls (0.87 +/- 0.19 vs 1.84 +/- 0.19 mM, Mean +/- SEM; n = 6) and gained less weight (2.55 +/- 0.37 vs 4.1 +/- 0.96 g/day, Mean +/- SEM; n = 6). There was no effect on female rats which received the same treatment. Spermatocoeles could also be produced by a single dose of 6-chloro-6-deoxyglucose, the threshold dose was between 180 and 240 mg/kg. Glucose oxidation by liver, brain, kidney and diaphragm from rats given 6-chloro-6-deoxyglucose (240 mg/kg/day for 14 days) was the same as in controls but was decreased in seminiferous tubules (0.32 +/- 0.06 vs 0.74 +/- 0.02 mumol [U-14C]glucose oxidised to 14CO2/g fresh wt/h, Mean +/- SEM; n = 3). The activity of glyceraldehyde-3-phosphate dehydrogenase [E.C. 1.2.1.12] in liver, brain, testis or muscle from rats given 6-chloro-6-deoxyglucose (24 mg/kg/day for 14 days) showed little change although its activity in spermatozoa was dramatically decreased.
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PMID:The effect of high doses of 6-chloro-6-deoxyglucose on the rat. 731 38

Mature epididymal boar spermatozoa converted fructose, glycerol and glycerol-3-phosphate to carbon dioxide, but in the presence of 0.5 mM 3-bromopyruvate, these oxidations were inhibited while that of lactate was unaffected. Inhibition of the oxidation of these substrates results in a decrease in the content of ATP and the accumulation of dihydroxyacetone phosphate and fructose-1,6-bisphosphate. Examination of the activities of the enzymes within stage two of the glycolytic pathway showed that glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase were immediately inhibited by 3-bromopyruvate in a competitive manner. We now report the action of 3-bromopyruvate on the metabolic activity of boar spermatozoa. At a concentration of 0.5 mM, this compound selectively inhibits stage two of the glycolytic pathway and becomes yet another specific inhibitor of spermatozoal metabolism.
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PMID:The anti-glycolytic activity of 3-bromopyruvate on mature boar spermatozoa in vitro. 858 90

The effectiveness of gossypol as an antifertilizing agent is due to the severe injuries or death that this drug produces on spermatozoa and spermatides. Several in vitro and in vivo studies have shown that spermatozoal lactic and malic dehydrogenases are inhibited by gossypol; and that these are more susceptible than the somatic enzymes. Notwithstanding, the in vivo effects on other somatic enzymes have been poorly analyzed. The present study shows that gossypol did not produce toxic effects on eight erythrocytic enzymes of male hamsters that were fed daily with 20 mg of gossypol/kg, for 1, 3, 5 or 10 days. The enzymatic activities analyzed were: adenylate kinase, hexokinase, glucose-6-phosphatase, glucose phosphoisomerase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglyceratokinase and pyruvate kinase.
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PMID:Orally administered gossypol has no effect on eight hamster erythrocytic enzymes. 874 2


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