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)

Sodium-potassium ATPase (Na+K(+)-ATPase) is a ubiquitous plasma membrane enzyme which uses the hydrolysis of ATP to regulate cellular Na+ and K+ levels and fluid volume. This ion pumping action is also thought to be involved in fluid movement across certain epithelia. There are several different genes for this enzyme, some of which are tissue specific. Using an antibody specific for the catalytic subunit of canine kidney Na+K(+)-ATPase, we have localized immunoreactivity in the seminiferous and epididymal epithelium of rats of various ages. There was no specific staining of 10-day-old rat testis. Faint staining was detected at 13 days and appeared to be associated with the borders of Sertoli cells. At 16 days prominent apical and lateral staining but no basal staining of Sertoli cell membranes was observed. This type of distribution continued until spermatids were present in the epithelium. In the adult rat testis, specific staining was detected in Sertoli cell crypts associated with elongating spermatids, and on the apical and lateral Sertoli cell membrane. In some instances immunoreactivity was concentrated at presumed sites of junctional specializations. In the excurrent ducts of immature and mature rats, Na+K(+)-ATPase staining was heavy in the efferent ducts and somewhat lighter in the epididymis. In all regions, the staining was basolateral although there were variations in intensity among the different parts of the epididymis. These results show 1) that rat testis and epididymal Na+K(+)-ATPase share some immunological determinants with the canine enzyme; 2) that the epididymal enzyme is located in the conventional basolateral position; and 3) that the distribution of Sertoli cell Na+K(+)-ATPase is probably apical and lateral rather than basal.
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PMID:Distribution of sodium-potassium ATPase in the rat testis and epididymis. 169 57

We found that anion channel blockers such as phosphotungstate and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) enhanced HCO3(-)-induced activation on porcine epididymal sperm. In the presence of these compounds, HCO3- increased the motility, respiration rate and especially the cAMP content of the sperm to a greater extent than did HCO3- alone. The enhancing effects were not observed in the absence of HCO3-, but were evident when the concentration of HCO3- was low. These compounds did not significantly alter the intracellular pH and did inhibit the adenylate cyclase activity of the sperm plasma membrane. When these compounds were added to sperm homogenate with ATP, the cAMP formed was reduced compared to the control. In addition, these compounds inhibited both the SO4(2-) influx and efflux of the sperm. From these results, we conclude that the anion channel blockers tested principally inhibit the efflux of endogenous HCO3- derived from metabolic CO2, so that HCO3- accumulates intracellularly and stimulates the adenylate cyclase of the sperm.
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PMID:The enhancing effects of anion channel blockers on sperm activation by bicarbonate. 169 90

4-Aminopyridine (4-AP) acts by blocking voltage dependent potassium channels in excitable membrane thus increasing the influx of extracellular (Ca2+) in response to an action potential. 4-AP exerts either in vivo or in vitro effects in many organs. The present report deals with a study on the electrically stimulated rat vas deferens of the action of 4-AP on Ca2+ mediated mechanism related to the adrenergic transmission. To avoid the interference of the non-adrenergic components we used the epididymal portion of the vas. 4-AP was shown to enhance the electrically-stimulated contractions in a way which was inversely related to external Ca2+. This effect was abolished by nifedipine (1 x 10(-6) M). Unexpectedly, however, 4-AP acted synergistically with nifedipine by enhancing the inhibition of the electrically-induced tension sustained by nifedipine. This property of 4-AP was shared by noradrenaline, phenylephrine, clonidine, serotonin, morphine and ATP. Their inhibitory effects were antagonized by prazosin (1 x 10(-8) M), yohimbine (2.5 x 10(-5) M), methysergide (1 x 10(-4) M), naloxone (1.2 x 10(-7) M), and theophylline (6 x 10(-6) M) respectively. The inhibitory effect of 4-AP was antagonized only by prazosin (1 x 10(-8) M) and was not observed in vas deferens of rats pretreated with reserpine. It is concluded that 4-AP is able not only to activate excitatory mechanisms but also to stimulate inhibitory alpha 1-adrenergic mechanisms.
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PMID:4-Aminopyridine activates an inhibitory alpha 1-adrenergic mechanism unmasked by nifedipin on the electrically stimulated rat vas deferens. 171 47

1. Guanethidine at 5 x 10(-6) M strongly inhibited rat prostatic but not epididymal vas deferens, reflecting differences in innervation and the neurogenic field stimulation responses of these tissues. 2. Adenosine and ATP inhibited the field stimulation responses of rat prostatic vas deferens by 56 and 50% respectively. A 10-min pretreatment with 10(-4) M caffeine partly reversed this inhibition, by 55% in the case of adenosine and 60% for ATP. 3. Pretreatment for 10 min with 5 microM quinidine failed to significantly alter the extent of either adenosine or ATP inhibition of the field stimulation responses of rat prostatic vas deferens. 4. 8-Phenyltheophylline, the selective blocker of the A1 subtype of the P1 receptor, partly reversed adenosine-induced inhibition of the vas deferens FS responses. NECA, the selective agonist of the A2 subtype of the P1 receptor, very strongly inhibited vas deferens FS responses. 5. Field stimulation responses of human vas deferens were also inhibited by both adenosine and ATP but to a lesser extent and more variably than in rat tissue. 6. Adenosine and ATP inhibition was reversed by caffeine pretreatment, but far more variably than in rat tissue, and quinidine was without significant effect on inhibition of the responses. 7. It is concluded that in these tissues adenosine and ATP may operate via a P1 type receptor of both A1 and A2 subtypes and that a P2 type receptor may be lacking.
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PMID:Purinergic modulation of field stimulation responses of rat and human vas deferens smooth muscle. 176 Nov 93

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

It has been suggested that alpha-glucosidase may be a marker of epididymal patency and function. Spermatozoal ATP concentrations decrease during passage through the epididymis, indicating efficient maturation. We correlated sperm motility with seminal plasma alpha-glucosidase activity and spermatozoal ATP. The sperm motility correlation with alpha-glucosidase activity was significantly positive, and the sperm motility correlation with spermatozoal ATP was significantly negative. It appears that high-alpha-glucosidase activity and low-spermatozoal ATP were present in semen with good sperm motility and could possibly indicate efficient epididymal function.
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PMID:alpha-Glucosidase, sperm ATP concentrations, and epididymal function. 187 46

Intact cauda-epididymal mature and caput-epididymal immature goat spermatozoa were assessed for their capacity to phosphorylate the outer surface proteins upon incubation in a modified Ringer's solution containing [delta-32P]ATP. The immature spermatozoa possessed markedly greater (approximately 7-fold) efficacy to phosphorylate the ecto-proteins than the mature cells. Autoradiographic analysis of the 32P-labelled proteins resolved by SDS-PAGE, showed that multiple sperm ecto-proteins are phosphorylated by an endogenous ecto-cyclic AMP-independent protein kinase (CIK) and the phosphorylation profile of these proteins underwent marked alteration during the epididymal sperm maturation. The intact caput-sperm as well showed nearly 4-fold higher specific activity of ecto-CIK than the cauda-sperm when the kinase activity was estimated using phosvitin as the exogenous protein substrate. The data suggest that the ecto-CIK and its specific protein substrates located on the sperm outer-surface, may have important roles in regulating the epididymal maturation of the male gametes.
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PMID:Alteration of the ecto-protein phosphorylation profile of intact goat spermatozoa during epididymal maturation. 187 97

Casein kinase II from bovine epididymal spermatozoa was purified to apparent homogeneity by repeated chromatography with phosphocellulose and gel filtration with sephacryl S-200. The purified enzyme exhibited a molecular mass of 130 kDa by gel filtration and displayed three polypeptide bands with molecular masses of 26, 33, and 36 kDa by SDS-polyacrylamide gel electrophoresis. Antibodies raised against calf thymus casein kinase II cross reacted with the three sperm polypeptides. Incubation of the holoenzyme with either [gamma-32P]ATP or [gamma-32P]GTP resulted in the phosphorylation of the 26-kDa subunit. The enzymatic activity with casein as substrate was strongly inhibited by nanomolar heparin and greatly stimulated by micromolar spermine. With casein as substrate, the specific activity of the pure enzyme (0.5 mumol/min/mg protein) was comparable to that of casein kinase II from other sources. Endogenous substrates of the kinase were demonstrated by incubating sperm cytosolic extracts with [gamma-32P]GTP, under conditions that limit the expression of other protein kinases, and analyzing the products by SDS-PAGE and autoradiography. Similar results were obtained when sperm extracts, suitably diluted to minimize endogenous casein kinase II, were incubated with [gamma-32P]GTP and aliquots of pure sperm casein kinase II. Low concentrations (50 microM) spermine strongly enhanced the phosphorylation of 92- and 106-kDa cytosolic proteins. Our results clearly show that casein kinase II is present in spermatozoa and that it shares many of the properties of the enzyme from other sources. Further, they indicate that the enzyme plays a role in mediating the phosphorylation state of sperm proteins.
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PMID:Purification and characterization of polyamine-stimulated protein kinase (casein kinase II) from bovine spermatozoa. 189 32

Low spermatozoal ATP concentration in the presence of high alpha-glucosidase activity may indicate efficient epididymal function. It was suggested that detached ciliary tufts (DCTs) originated from the epididymis. We compared the spermatozoal ATP concentration and alpha-glucosidase activity in semen of patients with DCTs to that of a control group. Higher ATP concentration and lower alpha-glucosidase activity were found in patients with DCTs in their semen compared to the control group. These results might probably point out impaired epididymal function and further support the proposed epididymal origin of these tufts.
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PMID:Impaired epididymal function in patients with detached ciliary tufts in semen: a preliminary report. 195 21

1. Most of the cyclic-nucleotide-independent acetyl-CoA carboxylase kinase activity in an extract of rat epididymal adipose tissue was evaluated from a Mono Q column by 0.175 M-NaCl at pH 7.4. The activity of the kinase in this fraction (fraction 1) was increased after exposure of intact tissue to insulin. 2. Incubation of purified adipose-tissue acetyl-CoA carboxylase with [gamma-32P]ATP and samples of fraction 1 led to the incorporation of up to 0.4 mol of 32P/mol of enzyme subunit. Most of the phosphorylation was on serine residues within a single tryptic peptide. This peptide, on the basis of two-dimensional t.l.c. analysis, h.p.l.c. and Superose 12 chromatography, appeared to be the same as the acetyl-CoA carboxylase peptide ('I'-peptide) which exhibits increased phosphorylation in insulin-treated tissue. 3. Phosphorylation of purified acetyl-CoA carboxylase by the kinase in fraction 1 was found to be associated with a parallel 4-fold increase in activity. However, increases in both phosphorylation and activity were much diminished if fraction 1 was treated by Centricon centrifugation to remove low-Mr components. Among these components was a potent inhibitor of acetyl-CoA carboxylase activity which appeared to be necessary for the kinase in fraction 1 to be fully active. 4. The inhibitor remains to be identified, but inhibition requires MgATP, although the inhibitor itself does not cause any phosphorylation of the carboxylase. No effects of insulin were observed on the activity of the inhibitor. 5. It is concluded that the kinase probably plays an important role in the mechanism whereby insulin brings about the well-established increases in phosphorylation and activation of acetyl-CoA carboxylase in adipose tissue.
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PMID:Protein-serine kinase from rat epididymal adipose tissue which phosphorylates and activates acetyl-CoA carboxylase. Possible role in insulin action. 197 70


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