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)

We report here the purification, partial characterization and immunofluorescent localization of a dimeric acidic glycoprotein (DAG-protein) secreted by cultures of Sertoli cells of rat testes. Partially purified protein was obtained after chromatography over Sepharose 4B under conditions which favored a soluble, nonaggregated form of the protein. Rechromatography over the same column under reducing conditions yielded very pure monomers of 41,000 daltons and 29,000 daltons. Antibodies were prepared against the mixed monomers and used to immunoprecipitate proteins in spent medium from cultures incubated with [35S] methionine, 35SO4 = or tunicamycin. DAG-protein and another protein (Band 4, 70,000 daltons) were coprecipitated by the antiserum and all contained 35SO4 = in their structures. It was shown by Western blotting that the antiserum cross-reacted very weakly with Band 4 protein. The DAG-protein polypeptides secreted in the presence of tunicamycin were assumed to lack N-glycosylation and exhibited apparent molecular weights of 27,000 and 21,000 daltons. Immunoprecipitations of media from organ cultures of testis and epididymis yielded DAG-protein of slightly lower molecular weight than the protein secreted in Sertoli cell cultures. Indirect immunofluorescence of DAG-protein in paraffin sections of testis and epididymis revealed that the protein was concentrated in the cytoplasm of Sertoli cells, on the stereocilia of epididymal principal cells, in the cytoplasm of epididymal halo cells, and was associated with late spermatids and mature sperm. Sperm were specifically labeled on the acrosome, at the neck, and on the endpiece of the tail. No enzymatic or structural function has been ascribed to DAG-protein as yet, but the protein must play a pivotal role in spermatogenesis because it is secreted by both the testis and epididymis and becomes an integral component of sperm.
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PMID:A sulfated glycoprotein synthesized by Sertoli cells and by epididymal cells is a component of the sperm membrane. 639 59

Protein secretion by the caput epididymidis has been examined in vitro using radioactive methionine as a precursor for protein synthesis. Newly synthesized and secreted proteins were separated by gel electrophoresis and visualized by fluorography. Local anesthetics such as procaine had the ability to reduce the secretion of some, but not all, proteins. Selective inhibition of secretion of the same proteins occurred when either dihydrocytochalasin B, monensin, ouabain, or dinitrophenol was added to the medium, or when the concentration of glucose was reduced below 1 mM. Calcium ionophore also selectively modified protein secretion, but the proteins affected were different from those influenced by local anesthetics. Other agents tested (eg, adrenergic and cholinergic agonists and antagonists, sodium pentobarbitone, antipsychotic drugs, cyclic AMP, colchicine) did not selectively modify protein secretion, even though overall protein synthesis and secretion was reduced in some instances. Procaine and dihydrocytochalasin B also reduced glucose utilization by epididymal tissue and it is suggested that these agents may reduce protein secretion by limiting the supply of energy for the exocytotic process. This conclusion is supported by the fact that dinitrophenol, an uncoupler of oxidative phosphorylation, caused a similar alteration in protein secretion. The possibility that a restricted energy supply modifies protein secretion primarily by creating a disturbed intracellular Na/K balance is suggested by the observation that the monovalent ionophore, monensin, and the Na/K ATPase inhibitor, ouabain, were both able to duplicate the effects of the local anesthetics.
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PMID:Protein secretion by the rat epididymis can be selectively modified in vitro by local anesthetics, glucose deprivation, dinitrophenol, ouabain, and ionophores. 643 36

Three factors were studied for their effects on the first cleavage division of in vitro fertilized hamster eggs. Eggs from superovulated females were inseminated with precapacitated epididymal hamster sperm in medium containing either fatty acid-free (FAF) or fraction V (V) bovine serum albumin (BSA), in the presence or absence of cumulus cells. After incubation for 3 to 4 h with sperm, eggs were transferred to culture medium containing FAF- or V-BSA, with or without amino acids (glutamine, isoleucine, methionine, and phenylalanine), and the percentages of eggs cleaving to two cells were recorded after a further 20 h of incubation. Fatty acid-free BSA was found to support a significantly higher percentage of eggs cleaving than V-BSA and was used in all further experiments. The presence of cumulus cells during fertilization was found to have a beneficial effect on cleavage when no amino acids were added to the culture medium, but when amino acids were included, eggs fertilized with or without cumulus present cleaved equally well. These results represent another step toward defining the optimal environmental conditions for obtaining the first cleavage division of hamster eggs in vitro.
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PMID:The effects of amino acids, cumulus cells, and bovine serum albumin on in vitro fertilization and first cleavage of hamster eggs. 668 53

Acidic epididymal glycoprotein (AEG) and androgen-binding protein (ABP) antisera were used to study functional activities of primary cell cultures of the epididymal epithelium of 20--23-day-old rats. Extensive AEG immunoreactivity was associated with almost all epithelial cells of the distal caput, corpus and cauda epididymidis. ABP immunoreactivity was solely confined to some epithelial cells of the caput epididymidis. AEG and ABP immunoreactive cells were identified as principal cells. Morphological studies of enzymically dispersed aggregates of the epididymal epithelial cells showed that stromal cells were satisfactorily removed and that cell aggregates consisted of a predominant population for cells displaying the morphological characteristics of principal cells. Scanning and transmission electron microscopic studies of cultured epididymal epithelial cells in monolayers demonstrated that microvilli and pit-like invaginations of the cell surface were preserved during the first 7--10 days of culture and then gradually disappeared. Other characteristic subcellular structures such as Golgi apparatus and rough endoplasmic reticulum cisterna were preserved. Electrophoretic analysis of [35S]methionine-labelled secretory polypeptides released by epididymal epithelial cells into the culture medium demonstrated a distinct protein band pattern which differed from that observed in the medium of cultured rat Sertoli cells. These results demonstrate that primary cultures of epididymal epithelial cells isolated from sexually immature rats maintain several differentiated characteristics of the intact organ and therefore provide a valuable system for the study of epididymal epithelial cell function.
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PMID:Structural and functional aspects of cultured epididymal epithelial cells isolated from pubertal rats. 675 17

The incorporation of radioactive mannose and fucose into secretory glycoproteins by rat epididymal tissue was studied using tissue pieces in vitro. The appearance of radioactive macromolecular products in the medium occurred after a lag phase of 2 h with radioactive mannose, but with radioactive fucose the lag phase was only 15 min. Preincubation of tissue for 2 h before the addition of radioactive mannose increased the subsequent rate of incorporation by reducing the lag phase from 2 to 1 h. Tunicamycin reduced the incorporation of radioactive mannose and fucose into macromolecular products to approximately 15 and 50% of normal in the caput and cauda respectively; maximum inhibition required 10 micrograms tunicamycin/ml in the caput and 2 micrograms/ml in the cauda. Reduction of radioactive sugar incorporation by tunicamycin did not result in qualitative changes in the profile of the radioactive glycoproteins that were secreted. However, immunoprecipitation of proteins D and E from incubations with radioactive methionine or mannose revealed that tunicamycin caused these proteins to be synthesized and secreted in a non-glycosylated form. Prior castration of animals reduced the incorporation of radioactive mannose and fucose, and qualitative changes in the profiles of secreted radioactive glycoproteins were apparent.
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PMID:Influence of incubation conditions, tunicamycin and castration on incorporation of [3H]mannose and [3H]fucose into rat epididymal glycoproteins in vitro. 682 79

The present report describes in vitro experiments with golden hamster sperm designed to determine whether there is any relationship between sperm phospholipid methylation and capacitation and/or the acrosome reaction. Washed cauda epididymal hamster sperm were incubated in a capacitation medium containing [methyl-3H] methionine. After 0.5, 1.5, 2.5 and 3.5 h of incubation, sperm were extracted with a chloroform:methanol:2 N HCl mixture to extract total phospholipids. Liquid scintillation counting revealed that the methyl-3H-group was incorporated into phospholipids with maximum incorporation at 3.5 h and an increase of 50% between 2.5 and 3.5 h. Uptake of labeled methionine by sperm reached its plateau by 1.5 h of incubation. Some sperm were capacitated by 3.5 h because that is the time at which the rate of acrosome reactions began to increase and because at least 50% of them were able to undergo the acrosome reaction 10 min after the addition of the fusogen lysophophatidylcholine (LPC) at 3.5 h but not at 2.5 h. Homocysteine thiolactone and 3-deazadenosine, inhibitors of transmethylation, inhibited incorporation of methyl-3H into phospholipids at 3.5 h by approximately 90% and also inhibited LPC-induced acrosome reactions by 60%. Separation of methylated sperm phospholipid by thin-layer chromatography demonstrated the presence of 3H-labeled phosphatidyl-N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine, and to a lesser extent phosphatidylcholine. In addition, an unidentified lipid was also highly labeled. These results strongly suggest a positive correlation between phospholipid methylation and capacitation and/or the acrosome reaction of hamster sperm in vitro. Possible mechanisms for phospholipid methylation involvement in these events are discussed.
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PMID:Phospholipid methylation increases during capacitation of golden hamster sperm in vitro. 687 7

The effect of amino acids on insulin responsiveness in epididymal adipose tissue was examined. It was found that insulin-stimulated glucose oxidation in fat cells was significantly inhibited by glycine, alanine, valine, leucine, isoleucine, cysteine, methionine, lysine, phenylalanine, and proline. The effect of insulin on glucose incorporation into triglyceride is also severely diminished by these amino acids. In addition, alanine reduced the incorporation of precursors ([U-14C]glucose or [1-14C]palmitate) into triglyceride both in vitro and in vivo. The Ki values of alanine were 0.4 and 0.5 mM toward the precursors of glucose and palmitate, respectively. The mechanism of reduction of insulin responsiveness in rat adipose tissue is discussed on the basis of these results.
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PMID:Effect of amino acids on insulin-stimulated glucose metabolism in fat cells. 701 47

The substrate specificity of rat testicular and epididymal peptidase was investigated using chromogenic substrates, D. L-alanine-, L-arginine-, gamma-N-L-glutamine-, L-leucine-, D. L-methionine-, alpha-N-benzoyl-D. L-arginine-, and N-benzoyl-L-leucine-beta-naphthylamide. The histochemical distribution of peptidase activity demonstrated with these substrates was also investigated in the testis and epididymis. L-Arginine-beta-raphthylamide (Arg-beta-NA) and gamma-N-L-glutamine-beta-naphthylamide (Glu-beta-NA) were mostly hydrolyzed in the testis and epididymis, respectively. Histologically, the activity using Arg-beta-NA as substrate (aminopeptidase B) appeared in both the cytoplasms and nuclei of interstitial cells and spermatogonia and the heads of spermatozoa, while activity using other substrates was found only in the cytoplasms of cells in the germinal epithelium. In the epididymis, strong reaction with Glu-beta-NA (gamma-glutamyl transpeptidase) was found in the apical part of the epithelial cells and in the heads of spermatozoa. Neither alpha-N-benzoyl-L-arginine- nor N-benzoyl-L-leucine-beta-naphthylamide was utilized in either the testis or the epididymis.
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PMID:Substrate specificity and histochemical distribution of aminopeptidase in rat testis and epididymis. 705 30

Skeletal muscle growth, muscle nucleic acids, and muscle protein synthesis and breakdown were measured to evaluate the protein requirement of weanling rats. Male Sprague-Dawley rats were fed purified diets that differed in protein and energy contents. Diets ranged from 5 to 30% casein, 5 to 15% corn oil, and all were methionine fortified. All diets were provided for 14 days beginning at 24 days of age. At 38 days of age, animals were killed and the soleus, plantaris, gastrocnemius, extensor digitorum longus (EDL), and biceps brachii muscles and the inguinal, epididymal, and perirenal fat pads were removed and weighed. The soleus and EDL were used to determine protein synthesis and breakdown and nucleic acid contents. Body weight, muscle weight, protein synthesis, DNA and RNA/DNA increased as the casein content of the diet increased to 15%. Casein levels up to 30% failed to cause any additional increases in any of these parameters. These findings indicate that for growing rats maximum protein synthesis defines the minimum about of dietary protein necessary to achieve maximum growth.
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PMID:Responses of skeletal muscle protein synthesis and breakdown to levels of dietary protein and fat during growth in weaning rats. 705 63

Protein synthesis has been investigated in different regions of the epididymis from normal rams, castrate rams, and castrate testosterone supplemented rams. Results show that there are few differences in the pattern of [35S]methionine-labelled proteins synthesized in different regions of the normal epididymis despite the variation in the morphology of the epithelial cells lining the duct. Three androgen-dependent proteins of molecular weights 24000, 64000 and approximately 200 000 were identified. Testosterone did not stimulate protein synthesis in the proximal caput epididymidis (region 1-3), suggesting that testicular fluid is important in maintaining the activity of epididymal cells in this area.
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PMID:Identification of androgen-dependent proteins synthesized in vitro by the ram epididymis. 715 95


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