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)

Nitric oxide gas (NO) increased guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] activity in soluble and particulate preparations from various tissues. The effect was dose-dependent and was observed with all tissue preparations examined. The extent of activation was variable among different tissue preparations and was greatest (19- to 33-fold) with supernatant fractions of homogenates from liver, lung, tracheal smooth muscle, heart, kidney, cerebral cortex, and cerebellum. Smaller effects (5- to 14-fold) were observed with supernatant fractions from skeletal muscle, spleen, intestinal muscle, adrenal, and epididymal fat. Activation was also observed with partially purified preparations of guanylate cyclase. Activation of rat liver supernatant preparations was augmented slightly with reducing agents, decreased with some oxidizing agents, and greater in a nitrogen than in an oxygen atmosphere. After activation with NO, guanylate cyclase activity decreased with a half-life of 3-4 at 4 degrees but re-exposure to NO resulted in reactivation of preparations. Sodium azide, sodium nitrite, hydroxylamine, and sodium nitroprusside also increased guanylate cyclase activity as reported previously. NO alone and in combination with these agents produced approximately the same degree of maximal activation, suggesting that all of these agents act through a similar mechanism. NO also increased the accumulation of cyclic GMP but not cyclic AMP in incubations of minces from various rat tissues. We propose that various nitro compounds and those capable of forming NO in incubations activate guanylate cyclase through a similar but undefined mechanism. These effects may explain the high activities of guanylate cyclase in certain tissues (e.g., lung and intestinal mucosa) that are exposed to environmental nitro compounds.
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PMID:Nitric oxide activates guanylate cyclase and increases guanosine 3':5'-cyclic monophosphate levels in various tissue preparations. 2 Jun 23

Experimental islet transplantations in pancreatectomized and streptozotocin-treated diabetic allogeneic and partially inbred rats are considered with respect to transplantation site and immunological factors responsible for survival. It could be shown that transplantation into the liver and into the lung in both systems (allogeneic and partially inbred) was accompanied by longer survival of the islets compared with the following regions: subcutaneous tissue, muscle, epididymal fat tissue, peritoneal cavity. This indicates that not only immunological but also factors of blood supply (oxygen consumption?)play a role in the survival of the grafts. - The success of transplantation depends mainly on histocompatibility. Partially inbred rats showed significantly longer survival of islets than non-inbred rats. The studies of other groups using similar experimental models are reviewed.
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PMID:Islet transplantation in experimental diabetes of the rat. IV. The influence of transplantation site and of histocompatibility on islet function. 13 Nov 3

Average lactate dehydrogenase (LDH) isoenzyme patterns the content of H subunits, total LDH activity, total malate dehydrogenase (MDH) activity and the m- MDH/s-MDH ratio were determined in twelve muscles and the male genital tract of the rabbit. LDH(1) was the predominant form in the heart, soleus and masseter muscles, LDH(3) in the lingual muscles and LDH(5) in the other muscles analysed. In the muscles, an increase in the percentual proportion of M subunits was accompanied, by a proportional increase in total LDH activity and a decrease in total MDH activity, especially m-MDH. LDH isoenzyme patterns and LDH and MDH activities are useful for obtaining some idea about the proportion of individual muscle fibres. Activity accounted for by H subunits was roughly the same in all the muscles analysed, indicating that the synthesis of H subunits is independent of the type of muscle fibre and of the oxygen supply of the muscular tissue, and also that isoenzymes composed chiefly of H subunits are not localized preferentially in the mitochondria. Similar relationships between LDH isoenzymes and LDH and MDH activities were found in the testicular and epididymal tissues. The tests and the head of the epididymis mainly contain LDH isoenzymes composed of H subunits. The total LDH activity in these tissues is relatively low and their MDH activity is relatively high compared with the body and tail of the epididymis. The proportion of H subunits in the ampulla, the seminal vesicles, the coagulating glands and the prostate is also high. Cowper's glands have a high LDH(5) and LDH(4) concentration. One of two LDHx isoenzymes were found in the testes and spermatozoa.
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PMID:Lactate and malate dehydrogenases in the muscles and male genital tract of the rabbit. 13

As it was shown previoulsy by others, the membrane-bound phosphodiesterase (cyclic adenosine 3':5'-monophosphate phosphodiesterase) of rat epididymal fat cells was stimulated when intact cells were exposed to insulin. The levels of stimulation observed in the present study in the cell homogenate and microsomal fraction were approximately 2.0- to 2.5-fold and 2.5- to 3.0-fold, respectively, when the initial substrate level was 100 nM and insulin concentration was 1 to 3 nM. When the microsomal fraction was subjected to a sucrose density gradient centrifugation, most of the insulin-sensitive phosphodiesterase activity was fractionated into the "light" microsomal fraction which was rich in NADH2:potassium ferricyanide:oxidoreductase) and low in 5'-AMPase, adenylate cyclase, and insulin-binding activities. The latter three activities were mostly fractionated into the "heavy" microsomal fraction. Both basal and insulin-stimulated phosphodiesterase activities were low when cells were homogenized in the presence of N-ethylmaleimide or p-chloromercuribenzoate. The insulin-stimulated enzyme activity was also low when cells were homogenized in the presence of --SH compounds (e.g. dithiothreitol) or certain metal-chelating agents (e.g. ethylene glycol bis(beta-aminoethyl ehter)-N,N'-tetraacetate (EGTA)), or in a nitrogen atmosphere. The effect of EGTA was prevented by the addition of certain heavy metal ions but not by the addition of Ca2+ or Ca2+ plus Mg2+ ions. When cells were homogenized in the presence of certain oxidants (e.g. diamide, sodium tetrathionate, or air), a high plus-insulin activity was observed; this activity was not lowered by subsequent treatment of the enzyme with N-ethylmaleimede, EGTA, or fresh cell homogenate that was prepared in the presence of EGTA. However, the activity of an apparently oxidized enzyme could still be lowered by treatment woth dithiothreitol. A partially purified enzyme in the enzyme in the microsomal fraction was fairly stable both in basal and insulin-stimulated states (fully active after 35 days when kept at -20degrees). EGTA added to the homogenization buffer lowered the basal phosphodiesterase activity, but this effect was reversed by the addition of Ca2+ ions. EGTA also decreased the enzyme activity that was stimulated by norepinephrine. However, neither EGTA nor dithiothreitol had any effect on the activities of 5'-AMPase, NADH-dehydrogenase, and malate dehydrogenase of fat cells. The above data indicate that most of the insulin-sensitive phosphodiesterase and the so-called "cell membrane markers" are associated with different subcellular particles in the cell homogenate. In addition, the data seem to indicate that the insulin-stimulated phosphodiesterase has certain --SH groups and that the activity of the enzyme is stabilized when the --SH groups are oxidized by certain oxidants including molecular oxygen. It is suggested that the air oxidation of the enzyme is catalyzed by a trace of certain heavy metal ions and, therefore, can be blocked by a metal-chelating agent.
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PMID:Insulin-sensitive phosphodiesterase. Its localization, hormonal stimulation, and oxidative stabilization. 17 Feb 71

Testicular and cauda epididymal sperm were obtained via catheters previously implanted in the rete testis and proximal vas deferens of bulls and were used to examine the relationships among sperm motility, cyclic adenosine 3':5'-monophosphate (cAMP) level, adenine nucleotide levels, and rates of glucose and oxygen consumption. Testicular, cauda epididymal, and ejaculated sperm contain cAMP-stimulated protein kinase, adenylate cyclase, and nucleotide phosphodiesterase. Treatment of the nonmotile testicular sperm with phosphodiesterase inhibitors resulted in a doubling of cellular cAMP concentration and a 25% increase in their glucose consumption. No change in motility, ATP level, or rate of oxygen consumption was observed. Sperm in neat cauda epididymal semen had flagellating tails but no progressive motility. Dilution of these sperm into glucose-containing buffer resulted in an increase in intracellular cAMP concentration and a decrease in ATP level with concomitant increases in ADP and AMP levels. These biochemical changes occurred within 30 s after dilution and apparently preceded the initiation of progressive motility by most cells. Since sperm in neat cauda epididymal semen became progressively motile when diluted with neat cauda epididymal plasma as well as accessory sex gland fluid or buffer, composition of the fluid surrounding the sperm is not responsible for the initiation of progressive motility upon dilution nor does cauda epididymal plasma contain an inhibitory factor. Perhaps release from contact immobilization provides the stimulation for the initial acquisition of progressive motility by cauda epididymal sperm. We conclude that during epididymal passage sperm develop from a cell physically unresponsive to changes in cAMP concentration to a form which initiates progressive motility upon changes in cAMP concentration.
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PMID:Adenine nucleotide changes at initiation of bull sperm motility. 17 61

The plasma level of free fatty acids (FFA) in adrenalectomized rats increases by 50% after treatment with aldosterone (2 microng/100 g rat). Lipolytic activity in peripheral fat tissue is lowered after adrenalectomy and doubles after in vivo administration of aldosterone to adrenalectomized rats (measured as free fatty acid release in vitro from epididymal fat tissue). Lypolysis of adipose tissue stimulated by the in vitro presence of ACTH also increases after in vivo administration of aldosterone. Incorporation of intravenously administered label from U-14C-palmitate into total extractable lipid of renal tissue is augmented 3 h after aldosterone administration to adrenalectomized rats, while no increase of the radioactivity is observed in total lipid from liver tissue. Treatment with aldosterone does not affect the total lipid content of kidney or liver in adrenalectomized rats. The oxygen consumption rate of kidney cortex slices with lactate, beta-hydroxybuterate or acetoacetate as substrates is lowered after in vivo administration of aldosterone to adrenalectomized rats. With slccinate, however, the respiratory rate of kidney slices increases after aldosterone treatment of adrenalectomized rats, the ouabain-sensitive respiration being more affected than the ouabain-insensitive respiration. An interpretation of the O2 consumption data implicating competition of lipid metabolism for CoA-SH is discussed.
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PMID:Effects of aldosterone on lipid metabolism and renal oxygen consumption in the rat. 55 89

The effects of a number of prostaglandins on the metabolism of fructose by epididymal and ejaculated ram spermatozoa were investigated using conventional Warburg techniques. Spermatozoa from the two sources were collected concurrently during electrical stimulation; the epididymal spermatozoa were harvested via a cannula inserted chronically into one vas deferens and thus were free from exposure to the seminal prostaglandins. In general, the metabolism of fructose by the spermatozoa was little affected by a wide range of prostaglandins at a concentration of 20 micrograms/ml. Of the PGs present in semen, PGE2, PGE3 and PGF2alpha had no significant effects whereas PGE1 and PGF1alpha significantly increased lactate accumulation and the latter increased oxygen uptake, in both cases without significantly changing fructose utilization, fructose oxidized or CO2 production. Both 15-methyl-substituted PGE2 and PGF2alpha and their corresponding methyl esters failed to change fructose metabolism and it is unlikely therefore that the lack of response to PGE2 and PGF2alpha was due to their being metabolized by the spermatozoa during the incubation. Of a number of breakdown products tested, PGA1 and to a lesser extent PGA2 appeared to inhibit the Krebs tricarbocyclic acid cycle and 15-keto 13,14-dihydro-PGF2alpha appeared to stimulate it. In general, epididymal spermatozoa responded to the PGs in the same way as ejaculated spermatozoa. Thus we did not confirm a suggestion in the literature that spermatozoa have lowered sensitivity to PGs in vitro once they have been in contact with the PGs in seminal plasma.
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PMID:Effect of various prostaglandins on the metabolism of fructose by epididymal and ejaculated ram spermatozoa in vitro. 73 77

Seven enzymes of the Embden-Myerhof pathway of glycolysis were assayed in hypotonically treated epididymal sperm from mature rabbits. These were: fructose-biphosphate aldolase, triosephosphate isomerase, glyceraldehydephosphate dehydrogenase, 3-phosphoglyceromutase, enolase, pyruvate kinase, and lactate dehydrogenase. These enzymes were firmly enough bound to the cell structure to resist removal by washing after hypotonic treatment and had maximal activities comparable to, or greater than, the rate of mitochondrial pyruvate oxidation, so that rapid oxygen uptake was observed with intermediates of the glycolytic pathway. The activity of lactate dehydrogenase in a typical preparation of hypotonically treated cells was 5.3 mumoles/minute x 10(9) cells at 25 degrees C for pyruvate reduction in the hypotonically treated cells and 4.8 mumoles/minute x 10(9) cells in the thrice-washed hypotonically treated cells. The Km for pyruvate was 1.4 mM while that for lactate was 4.4 mM. By contrast, the maximal activity of pyruvate oxidation by mitochondria was 0.10 microgram atom of oxygen/minute x 10(9) cells, corresponding to 0.020 mumole of pyruvate/minute x 10(9) cells, and the Km for pyruvate was 5 microM. These enzyme parameters favor high lactate production from glucose in aerobic glycolysis.
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PMID:Energy metabolism of spermatozoa. V. The Embden-Myerhof pathway of glycolysis: activities of pathway enzymes in hypotonically treated rabbit epididymal spermatozoa. 80 42

Spermatozoa were collected from the rete testis and vas deferens of conscious rams. The endogenous oxygen uptake of the spermatozoa was unaffected by alpha-chlorohydrin added in vitro, although this compound abolished the stimulation of oxygen uptake caused by the addition of glycerol. The metabolism of [14C]glycerol by testicular and epididymal spermatozoa was markedly reduced by alpha-chlorohydrin, CO2 production and lactate accumulation being almost totally inhibited. These effects were dependent upon a period of preincubation of the spermatozoa with alpha-chlorohydrin alone, since the presence of glycerol protected the spermatozoa from its action. Longer exposure and a higher concentration of alpha-chlorohydrin were needed with testicular than with epididymal spermatozoa to achieve a maximal effect. The metabolism of [14C]glucose by both sperm types was also inhibited by alpha-chlorohyrin. Spermatozoa of the ram are therefore susceptible to the action of alpha-chlorohydrin throughout the epididymis, although more mature spermatozoa are more affected. It is suggested that alpha-chlorohydrin is converted to an intermediate which is the agent responsible for the inhibition of glycolysis in spermatozoa.
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PMID:Effects of alpha-chlorohydrin on the metabolism of testicular and epididymal spermatozoa of rams. 99 97

Changes in the concentration of -SH groups on the human and rabbit spermatozoal membrane and during epididymal maturation were studied by means of a new fluorescent probe, carboxyphenylmaleimide (CPhM), which reacts specifically with -SH groups. Binding of CPhM did not modify oxygen uptake, motility, or viability of the sperm cells used, but produced a characteristic increase in fluorescence. By analysis of this increase it was possible to calculate the presence of 35 +/- 4.2 and 55 +/- 8 nmoles of exposed -SH groups/10(8) rabbit and human ejaculated spermatozoa, respectively. Caput epididymal cells bound significantly more CPhM than did cauda epididymal cells or ejaculated spermatozoa (155 +/- 22, 78 +/- 11, and 35 +/- 4.2 nmoles/10(8) cells, respectively, in rabbit cells; and 184, 110 +/- 18, and 55 +/- 8 nmoles/10(8) cells, respectively, in humans cells). In addition to the differences in number of exposed -SH groups observed between human and rabbit sperm cells, the behavior of these membrane-reactive groups when ethylenediaminetetraacetate and/or zinc were added to the incubation media indicates that the participation of membrane--SH groups in sperm physiology is species-specific.
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PMID:Participation of membrane sulfhydryl groups in the epididymal maturation of human and rabbit spermatozoa. 100 33


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