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Query: UNIPROT:P56851 (epididymal)
 11,273 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

Weaning rats were submitted during 3 months to complet and balanced diets where only glucidic constituent varied. They were sacrified when fed or after 16 h fasting. 1. The value of intestinal sucrose K(M) is higher in rats fed on glucose dietary than in rats fed on sucrose, fructose or glucose + fructose dietary. These modifications are independant of the states of digestion. 2. The V(MAX) is diversely influenced by the states of digestion: hydric diet increases the V(MAX) in animals fed on sucrose diet when intestinal repletion has the same effect in animals receiving glucose diet. Fructose diet decreases it irreversibility in both cases. 3. Growth of animals is sagging respectively in order from sucrose and glucose diets to glucose + fructose and fructose diets, then weight of organes is unaffected. It was noted that perirenal and epididymal fats are more abundant in rats nourished with glucose diet than with fructose diet. 4. The glucoregulation is correctly effectued in either starved or fed animals and shows an available adaptation of organism in energetic utilisation of various studied sugars. Plasmatic, hepatis and intestinal free fatty acids levels are constant and equal in all series of expements in spite of important variations of reverse fat.
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PMID:[Responses and physiological modifications of intestinal sucrase in rats fed diets containing various carbohydrates]. 97 Aug 35

beta-Galactosidase, known to be secreted by epithelial cells lining the rat epididymal duct, binds to the surface of spermatozoa from the caudal region with high affinity and in a saturable form. The binding was not inhibited by mannose-6-phosphate, but was inhibited by fructose phosphate derivatives, a peculiarity previously demonstrated for the membranes of epididymal tissue. Fructose phosphate derivatives released 55% of beta-galactosidase activity from the spermatozoa. These results suggest that in the epididymis there is a special transport system for hydrolases, which could be involved in the secretion of enzymes destined for spermatozoa. This transport would require receptors that recognize sugar ligands other than mannose-6-phosphate. These receptors were present in the epididymal tissue and on the sperm surface.
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PMID:Binding of beta-galactosidase from rat epididymal fluid to the sperm surface by high-affinity sites different from phosphomannosyl receptors. 178 47

Mature epididymal boar spermatozoa converted glucose and fructose to carbon dioxide and lactate and maintained high concentrations of ATP. In the presence of (S)-alpha-chlorohydrin these processes were inhibited and there was an accumulation of fructose-1,6-bisphosphate and dihydroxyacetone phosphate. With fructose-1,6-bisphosphate as the substrate, the concentration of ATP was maintained, carbon dioxide was evolved and dihydroxyacetone phosphate accumulated. Cells pre-incubated with (S)-alpha-chlorohydrin did not maintain ATP levels, evolved less carbon dioxide and produced dihydroxyacetone phosphate. Assays of incubates in which fructose-1,6-bisphosphate was used as the substrate showed the presence of equilibrium quantities of fructose-6-phosphate and glucose-6-phosphate which were not detected when either fructose or glucose were used as substrates. [14C]Fructose and [14C]glucose were not produced from [14C]fructose-1,6-bisphosphate in spermatozoal incubates which had or had not been pre-incubated with (S)-alpha-chlorohydrin. Evidence is presented that a high concentration of fructose-1,6-bisphosphate leads to the formation of fructose-6-phosphate and glucose-6-phosphate but not of fructose and/or glucose.
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PMID:Metabolism of fructose-1,6-bisphosphate by mature boar spermatozoa. 178 2

Fructose levels and fructolysis index in human semen were analysed to assess a correlation, if any, between the levels of this glycolysable sugar and sperm concentration. Semen was collected from normospermic men and men with azoospermia or oligospermia. Seminal fructose levels were elevated in men with obstructive azoospermia and in men who remained azoospermic following vasoepididy mostomy done to correct epididymal blockage. Men with sperm concentration of less than 20 million/ml pre-operatively or following vasoepididy mostomy, showed significantly high levels of fructose and lower fructolysis index. Fructose levels in normospermic infertile men, as well as in men with normal sperm counts (more than 20 million/ml), were similar to that in men of proven fertility.
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PMID:Seminal fructose in normal and infertile men. 271 90

Mature porcine sperm preserved in the cauda epididymis are quiescent. At ejaculation, they are mixed with the seminal vesicle fluid containing HCO3- and are rapidly activated. The role of HCO3- on the sperm activation process at ejaculation was studied in vitro. HCO3- quickly increased the motility, respiration rate and cAMP content of the porcine epididymal sperm. The extent of activation was proportional to the pCO2 in the medium. The activating effect of HCO3- on the motility was observed even in the absence of fructose as well as in the presence of KCN. 8-Bromoadenosine 3',5'-cyclic monophosphate and theophylline showed similar activating effects to that of HCO3-. However, HCO3(-)-free seminal plasma, Ca2+, amino acids, intermediates of the Krebs cycle, substrates of respiration and increases in the intracellular pH, extracellular pH or ionic strength of the medium had no effect. Fructose sustained the active state of the sperm and gradually increased both the motility and respiration rate when the dose of HCO3- was low. The anion channel blocker enhanced the activating effect of HCO3-. These results suggest that, upon ejaculation, HCO3- is a unique activator in vivo which makes the quiescent sperm motile via the HCO3(-)-adenylate cyclase-cAMP system, to which an endogenous HCO3- derived from metabolic CO2 may be related.
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PMID:The activating effects of bicarbonate on sperm motility and respiration at ejaculation. 303 42

The origin of glycerylphosphorylcholine (GPC), N-acetylaminosugar, inositol, and prostaglandins in human seminal plasma was investigated by correlating the concentration of these components in split ejaculates with known marker constituents. Fructose and acid phosphatase were selected as markers of the secretory activity of the seminal vesicles and prostate gland, respectively, and spermatozoa indicated epididymal origin. The concentration of fructose was lowest in the first fraction of the semen and increased to a maximum in the final portion. Prostaglandins E and F and N-acetylaminosugar values closely followed this pattern, indicating that these components originate in the seminal vesicles. The concentration of spermatozoa was high in the first two fractions, decreasing to a minimum in the final fraction. The distribution of GPC was similar to that of the spermatozoa, indicating that the epididymis secretes this compound. Inositol levels were similar in all fractions, indicating that it is probably present in epididymal, vesicular, and prostatic fluid. Human spermatozoa were unable to utilize N-acetylglucosamine or inositol. High concentrations of some prostaglandins (100 micrograms/ml of PGF1 alpha, 15S 15 met. F2 alpha, PGA1, and PGA2) depressed the endogenous oxygen uptake of human spermatozoa.
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PMID:Origin of glycerylphosphorylcholine, inositol, N-acetylaminosugar, and prostaglandins in human seminal plasma and their effects on sperm metabolism. 736 41

To study the cellular mechanisms underlying fructose-induced insulin resistance in rats, the effects of fructose feeding on insulin-stimulated glucose transport, oxidation and incorporation into lipids in epididymal adipocytes were evaluated in 27 normal and 27 noninsulin-dependent diabetic male Sprague-Dawley rats. Diabetes was induced by streptozotocin injection 2 d after birth. At 5 wk of age, both normal and diabetic rats were fed a diet containing 62% carbohydrate as fructose, dextrose or cornstarch. Fructose feeding for 6 wk induced glucose intolerance in normal rats (P < 0.05) and aggravated that of diabetic rats (P < 0.05). Plasma triacylglycerol concentration was higher in fructose-fed than in starch-fed or dextrose-fed rats (P < 0.05). Adipocytes of fructose-fed rats had significantly lower maximum insulin-stimulated glucose incorporation into total lipids than those of rats fed starch, and tended (P = 0.22) to have lower production of CO2 from glucose than adipocytes of the other dietary groups. Glucose transport in adipocytes of dextrose-, starch- and fructose-fed rats did not differ. We conclude that in both normal and diabetic rats, a chronic fructose-rich diet induced hypertriacylglycerolemia, glucose intolerance and insulin resistance of adipocytes.
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PMID:A fructose-rich diet decreases insulin-stimulated glucose incorporation into lipids but not glucose transport in adipocytes of normal and diabetic rats. 786 Dec 42

The binding of N-acetyl-beta-D-glucosaminidase from rat epididymal fluid to the surface of spermatozoa from the cauda epididymis was measured in the presence of sugars, its phosphorylated derivatives, or after treatment of the cells or the enzyme with agents that alter the integrity of proteins or carbohydrates. The binding was saturable, with a Kd in the nanomolar range, was inhibited with phosphorylated derivates of fructose, and did not depend on Ca2+, showing that it is different from the mannose 6-P-recognizing system existing in other tissues for this and other acid hydrolases. Treatment of the cells with sodium periodate or trypsin inhibited the binding, showing that a glycoprotein of the plasmalemma is involved in the affinity site. Fructose or phosphorylated derivates were not detected in the proteins of the epididymal fluid with HPLC. However, with the method used, the presence of these compounds cannot be ruled out, if among the proteins of the fluid there are only a small number of acid hydrolases containing this sugar.
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PMID:Affinity sites for N-acetyl-beta-D-glucosaminidase on the surface of rat epididymal spermatozoa. 800 7

The origin of seminal leucocytes and their biological significance were investigated in 76 whole ejaculate samples and 27 split ejaculate samples, obtained from patients attending the Zimbabwe Family Planning Council's Spilhaus Infertility Clinic at Harare. The leucocytes were more prevalent in fractions 1 and 2 than in fraction 3, implying that the testis, epididymis and prostate are the major sources of seminal leucocytes. The contribution from the seminal vesicles was minimal. An inverse relation is apparent between leucocyte count and sperm count (p < 0.01). The percentage of abnormal sperms was higher (p < 0.05) and the sperm motility poorer in leucocytospermic samples (p < 0.01). Fructose, the seminal vesicular marker, citric acid, the prostatic marker and alpha-glucosidase, the epididymal marker were not decreased in leucocytospermia. It is concluded that the epididymis and prostate are the major contributors of granulocytes in semen. Leucocytospermia affects sperm morphology and sperm motility but not the accessory sex gland functions. Probably these cytotoxic effects are mediated by hydrogen peroxide due to activation of seminal leucocytes. However, the presence of leucocytospermia in normozoospermic samples is indicative of the possible peaceful coexistence of leucocytes and sperms.
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PMID:Study on the origin of seminal leucocytes using split ejaculate technique and the effect of leucocytospermia on sperm characteristics. 987 48


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