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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endothelin, a novel potent vasoconstrictor peptide produced by vascular endothelial cells, stimulated anion secretion by a cultured secretory epithelium derived from the rat epididymis as measured by changes in short-circuit current (SCC). Stimulation of the SCC was observed when endothelin was added to the basolateral or the apical side of the epithelium. The response to basolateral application was greater than that to apical application. The EC50 values were found to be 1.3 and 3.0 nM for basolateral and apical application, respectively. These values were about one-half to one order of magnitude higher than that required for its vasoconstrictor action. The stimulation of SCC by endothelin was likely to be due to an increase to anion secretion as removal of Cl from the incubation medium markedly reduced the SCC response to endothelin. Diphenylamine-2-carboxylate (DPC, 0.1 mM), a Cl-channel blocker, added to the apical side also inhibited the endothelin-induced rise in SCC. The stimulation of SCC by endothelin was accompanied by a rise in the intracellular cyclic AMP content in epididymal monolayers. Immunofluorescence staining has shown the presence of immunoreactive endothelin-like compound in the interstitium and epithelial cells of the rat epididymis. It is speculated that endogenous endothelin plays an important role in the control of water and electrolyte transport in the epididymis.
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PMID:Functional study and immunocytochemical identification of endothelin in cultured epididymal cells and intact epididymis of the rat. 172 45

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

Primary monolayer cultures of rat epididymal cells have been shown to secrete chloride and bicarbonate when stimulated with beta-adrenergic agents, humoral agents and vasoactive peptides. The intracellular messengers mediating the secretory response are unknown. In this study intracellular AMP, Ca2+ and inositol phosphates were measured in epididymal monolayers at rest and upon stimulation with various secretory agonists. Adrenaline, forskolin, lysylbradykinin, prostaglandin, endothelin, angiotensin II, antidiuretic hormone and vasoactive intestinal peptide at concentrations that stimulate anion secretion caused a rise in intracellular cyclic AMP. The increase in cyclic AMP by adrenaline was blocked by propranolol but not by phentolamine. Studies of the concentration-effect relationships showed that for adrenaline and endothelin the EC50 for stimulation of cyclic AMP was higher than that for stimulation of anion secretion. None of these agonists affects intracellular Ca2+ concentration and inositol phosphate contents in epididymal monolayers. Ca2+ ionophores A21387, ionomycin and erythrosin B (with irradiation with white light), at concentrations that stimulate anion secretion, also stimulated a rise in intracellular cyclic AMP and concomitantly increased intracellular Ca2+. The increase in cyclic AMP was dependent on extracellular Ca2+. It is not known whether the secretory response to Ca2+ ionophores was mediated by an increase in cell Ca2+ per se, or cyclic AMP. However, it can be concluded that cyclic AMP is the second messenger which mediates the secretory responses to physiological stimuli.
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PMID:Secretory agonists stimulate a rise in intracellular cyclic AMP but not Ca2+ and inositol phosphates in cultured rat epididymal epithelium. 197 25

Goat cauda-epididymal intact sperm ecto [32P] proteins phosphorylated in presence of exogenous [gamma-32P]ATP by an endogenous ecto-cyclic AMP-independent protein kinase (CIK), have been found to lose 32P when the labelled cells are incubated at 37 degrees C in a modified Ringer's solution. Analysis of the 32P-labelled products of the turnover of the ecto-phosphoproteins show that 32Pi rather than 32P-labelled peptides, is released from the cell-surface phosphoproteins indicating that the turnover of the ecto-phosphoproteins is mediated by an endogenous sperm outer-surface phosphoprotein phosphatase (ecto-PPase). The ecto-PPase is not a non-specific phosphatase since unlabelled p-nitrophenyl phosphate, beta-glycerophosphate or ATP at a relatively high concentration (1 mM each) has no appreciable effect on the dephosphorylation of the cell-surface proteins. The intact-sperm ecto-proteins phosphorylated and then dephosphorylated by the endogenous ecto-CIK and PPase respectively, undergo rephosphorylation by the cell-surface CIK. The data are consistent with the view that sperm external surface possesses a novel coupled-ecto-CIK and PPase enzyme system that regulates the phosphorylated states of the intact-sperm ecto-proteins by a cyclic mechanism of protein phosphorylation and dephosphorylation.
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PMID:Occurrence of a coupled-enzyme system on the intact-sperm outer surface that phosphorylates and dephosphorylates ecto-proteins. 216 95

An earlier report from this laboratory showed that feeding rats a high fat diet decreased epinephrine-stimulated lipolysis in their adipose tissue. Experiments were designed to explore further the effects of such diets on adipocyte response to epinephrine and to several other lipolytic and antilipolytic agents. Rats were fed diets with 67% of energy consisting of glucose or lard for 5 to 7 d. Adipocytes were prepared from epididymal fat pads and lipolysis measured by the release of glycerol into the medium during 1-h incubations. The cells from the rats fed the high fat diet showed lower lipolytic responses to stimulation by epinephrine, forskolin and dibutyryl cyclic AMP than those from rats fed the high glucose diet. The lard diet effect on the lipolytic response to isobutylmethylxanthine varied among experiments, but it also decreased it in some of them. However, the high fat diet did not induce decreased sensitivity or responsiveness to the antilipolytic effect of insulin, although previous reports have demonstrated resistance to other actions of insulin in rats fed a high fat diet. The antilipolytic effect of nicotinic acid was also similar in cells from rats fed a high fat diet to that found for cells from rats fed the high glucose diet.
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PMID:Effect of a high fat diet on rat adipocyte lipolysis: responses to epinephrine, forskolin, methylisobutylxanthine, dibutyryl cyclic AMP, insulin and nicotinic acid. 243 78

A reproducible cell culture system is described that allows the study of adipose conversion in fibroblast-like cells isolated by collagenase digestion of epididymal and perirenal adipose tissue from male rats weighing 70-200 g. Adipose conversion as measured by lipid accumulation and increase in glycerophosphate dehydrogenase (GPDH) activity during differentiation strongly depends on the density at which cells are inoculated and starts only when cells are confluent and when physiological amounts of corticosterone and insulin are added. beta-Estradiol, testosterone, thyroxine, triiodothyronine, and growth hormone do not affect the differentiation process. Methylisobutylxanthine added during the first 2 days after confluence, added with insulin and corticosterone, potentiates the effect of insulin on GPDH activity and accelerates triglyceride accumulation. The effect of methyl-isobutylxanthine seems to be mediated by increased cyclic AMP concentrations, inasmuch as it may be replaced by forskolin.
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PMID:Hormonal regulation of the differentiation of rat adipocyte precursor cells in primary culture. 244 Sep 70

When confluent cultures of cloned mouse 3T3-L1 cells were differentiated to adipocytes by three days of treatment with a combination of 0.5 microM dexamethasone and 0.5 mM 1-methyl-3-isobutylxanthine, the S100 protein content in the cells increased markedly, as determined by a sensitive immunoassay system. The S100 protein induced in the cell was the alpha alpha form (S100ao), which is the predominant form of S100 protein in mouse adipose tissue. The S100ao concentration in preadipocytes was about 1-3 ng/mg protein, while the concentration in differentiated adipocytes was 60-200 ng/mg protein. The immunoblotting test of the crude extract of adipocytes confirmed that the immunoreactive substance in the cells was the alpha subunit of S100 protein. The treatment with 1-methyl-3-isobutylxanthine or dexamethasone alone neither elicited the S100 protein induction nor triacylglycerols accumulation in the cells. The accumulation of triacyglycerols in the cells was always preceded by the induction of S100ao protein under conditions where the differentiation to adipocytes was elicited. The induction of S100ao protein and accumulation of triacylglycerols in the cells treated with dexamethasone and 1-methyl-3-isobutylxanthine were inhibited by the addition of antimicrotubular drugs, colchicine and vinblastine, but not by cytochalasin B, an antimicrofilament drug. S100ao protein in 3T3-L1 adipocytes was released by incubation with a lipolytic hormone, adrenocorticotropic hormone or catecholamines, in a cyclic-AMP-dependent manner as observed with rat epididymal fat pads [Biochim. Biophys. Acta (1986) 889, 84-90]. These results also suggest that S100 protein may participate in the function of adipocytes.
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PMID:Induction of S100 protein in 3T3-L1 cells during differentiation to adipocytes and its liberating by lipolytic hormones. 246 4

1. Endothelin, a novel potent vasoconstrictor peptide produced by vascular endothelial cells stimulated anion secretion by a cultured secretory epithelium derived from the rat epididymis as measured by changes in short-circuit current (SCC). 2. Stimulation of the SCC was observed when endothelin was added to the basolateral or the apical side of the epithelium. The response to basolateral application was greater than that to apical application. The EC50 values were found to be 1.3 nM and 3.0 nM for basolateral and apical application, respectively. These values were about half an order to one order of magnitude higher than that required for its vasoconstrictor action. 3. The stimulation of SCC by endothelin was accompanied by a rise in the intracellular adenosine 3':5'-cyclic monophosphate (cyclic AMP) content in epididymal monolayers. 4. The effect of endothelin on SCC was mediated through an increase in prostaglandin synthesis by the tissues and was not blocked by an antagonist of angiotensin II (Sar1 Ile8 angiotensin II) or of adrenaline (propranolol). 5. It is speculated that endogenous endothelin plays an important role in the control of water and electrolyte transport in the epididymis.
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PMID:Endothelin stimulates short circuit current in a cultured epithelium. 248

Goat epididymal intact spermatozoa have been shown to possess on the external surface specific receptors that bind with high affinity to exogenous [8-3H]cyclic AMP. The ecto-cyclic AMP-receptor activity was not due to contamination of broken or "leaky" cells, if any. The binding reaction of [3H]cyclic AMP with the receptors was extremely rapid. Uptake of the labeled cyclic AMP to the sperm cytosolic fraction was undetectable. There was little leakage of cyclic AMP-receptors from intact spermatozoa during the binding assays. The binding reaction was proportional to cell concentration, specific and saturable at 250 nM cyclic AMP. The binding of the labelled cyclic nucleotide was nearly completely displaced at saturating concentrations (2.5 microM) of the unlabelled nucleotide. The ecto-receptors showed high specificity for binding to cyclic AMP. The Kd of the binding sites was approximately 1.7 X 10(-8) M. The binding interaction was highly sensitive to treatment with proteolytic enzymes: trypsin, chymotrypsin, or pronase (125 micrograms/ml). Sonication caused a nearly 450% increase of the ecto-receptor activity. The specific activity of the ecto-cyclic AMP-receptor was approximately twofold higher in the vigorously forwardly motile spermatozoa than in the "composite" cells, suggesting that the ecto-receptors may have a role in modulating flagellar motility.
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PMID:Ecto-cyclic AMP-receptor in goat epididymal intact spermatozoa and its change in activity during forward motility. 282 7

Carbenoxolone significantly decreased the glucose uptake and the incorporation of glucose into triglycerides and CO2 in rat epididymal fat pads. The effect produced by insulin on these metabolic pathways was reduced when adipose tissue was incubated with insulin in the presence of carbenoxolone (10(-3) M). On the other hand the drug (10(-3) M) produced a decrease in cyclic AMP concentration in adipose tissue similar to that produced by insulin (100 ng/ml).
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PMID:Effect of carbenoxolone on glucose metabolism in rat adipose tissue. 283 77


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