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

Previous studies showed that interspecies differences in proacrosin size may exist. We purified guinea pig proacrosins, one from testes and two from epididymal spermatozoa, by gel filtration and cation exchange at acidic pH. Final purification was by cation exchange at pH 8.0 in 6 M urea. Testis proacrosin migrated with 62,000 Mr in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). One sperm proacrosin migrated with 43,000 Mr, and the other as a 56,000/54,000 Mr doublet in SDS-PAGE. These results represent the first purification of three forms of proacrosin from one species, and the first purification to homogeneity of a 43,000 Mr proacrosin. The proacrosins autoactivate at pH 8.0 with similar kinetics, copurify until the last purification step, and share antigenic determinants. It is possible that the sperm proacrosins are derived from the testis proacrosin, perhaps by proteolysis. The sizes of the three guinea pig proacrosins reported in this study are similar to those reported for proacrosins from other species. Apparent interspecies differences in proacrosin size may be primarily a question of which of at least three possible forms of the zymogen predominates in a species.
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PMID:Purification and initial characterization of proacrosins from guinea pig testes and epididymal spermatozoa. 311 22

Using immunoblot analysis, we examined the electrophoretic mobility of glycogen synthase from rat skeletal muscle and adipose tissue. Extracts from muscle freeze clamped in situ contained at least three forms of synthase with different electrophoretic mobilities. Extracts from adipose tissue also contained multiple forms but lacked the form with greatest mobility found in the muscle extracts. Phosphorylation at multiple sites of glycogen synthase is known to deactivate the enzyme and retard its electrophoretic mobility in sodium dodecyl sulfate gels. These results suggest that there is very little or no dephosphorylated glycogen synthase in adipose tissue and that phosphorylated forms of glycogen synthase synthesize adipose tissue glycogen. Relative to control, it is known that fasting decreases and refeeding increases glucose incorporation into glycogen in rat epididymal adipose tissue but not skeletal muscle incubated in vitro in the presence of insulin. Fasting did not change the electrophoretic pattern of muscle synthase but decreased the relative amount of adipose tissue forms with greater mobility. Refeeding increased above control the relative amount of adipose tissue synthase with greater mobility. These results indicate that changes in the phosphorylations that retard mobility contribute to the effects of fasting and refeeding on adipose tissue glycogen metabolism.
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PMID:Regulation of glycogen synthase in muscle and adipose tissue during fasting and refeeding. 313 46

Using a partially purified enzyme preparation obtained from hamster epididymis, a simple assay has been developed to measure the sulfurylation of dehydroisoandrosterone (DHA) and desmosterol in the presence of 3'-phosphoadenosine 5'-phospho[35S]sulfate [( 35S]PAPS). After stopping the enzymatic reaction with methanol and KCl, the 35S-labelled steroid sulfates are readily extracted into an organic phase. Optimal conditions for the sulfurylation of the two steroids were compared; optimum pH is 8.7 for DHA and 9.8 for desmosterol. Sulfoconjugation of desmosterol increases with magnesium concentrations up to 6 mM, while 40 mM concentrations of the divalent ion are required for the optimal sulfurylation of DHA. Maximum sulfurylation of these steroids requires the presence of 15 mM cysteine. Michaelis-Menten kinetics are observed with DHA which has an apparent Km of 32 microM, while desmosterol inhibits sulfotransferase activity at high concentrations. Saturation of the enzyme with PAPS results in an allosteric behaviour. Only the 3 beta-hydroxyl function of the steroid nucleus appears to be an appropriate sulfate acceptor for the epididymal hydroxysteroid sulfotransferase.
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PMID:The assay and partial characterization of 3 beta-hydroxysteroid sulfotransferase of the hamster epididymis. 315 30

Vasectomy was performed on inbred Lewis rats to induce anti-sperm autoantibodies and to identify their cognate autoantigens. Different detergent extracts of cauda epididymal spermatozoa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotted to nitrocellulose, and probed with sera from pre-vasectomy, post-vasectomy, and hyperimmunized animals to detect isologous sperm antigens. Nonreduced SDS-soluble autoantigens at greater than 200, 86, 43, and 26 kDa were bound by post-vasectomy antisera. Reduction of SDS-soluble antigens resulted in increased staining of the 86, 72-63, and 43 kDa autoantigens. Laemmli extraction of SDS insoluble pellets with beta-mercaptoethanol generated the largest repertoire of autoantigens including several autoantigens found in SDS-soluble extracts. Therefore, to analyze the entire repertoire of post-vasectomy autoantigens, whole sperm were extracted with Laemmli buffer under reducing conditions. Autoantiserum from most vasectomized animals bound Laemmli-extracted reduced autoantigens of approximately 86 (89-78), 63, 43, and 20 (21-16) kDa. Testicular extracts, reduced and separated by SDS-PAGE, contained autoantigens of 76, 60, and 42 kDa that were also recognized by hyperimmune and post-vasectomy antisera. The repertoire of sperm antigens recognized by pooled serum from hyperimmunized animals was similar to the cumulative repertoire recognized by post-vasectomy sera. These studies define several major sperm autoimmunogens recognized by post-vasectomy antisera and indicate that many of these peptide autoimmunogens are disulfide-bonded complexes.
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PMID:Post-vasectomy sperm autoimmunogens in the Lewis rat. 326 39

The expression, properties and relationship of two mouse embryonic antigens (TEC-1 and TEC-2), which are defined by monoclonal antibodies, were investigated in the epididymis of four rodent species. Absorption analysis, indirect immunofluorescence microscopy and immunohistochemistry revealed that all the species studied contained in their epididymides, but not in testes, either TEC-1 (Chinese hamster), TEC-2 (guinea pigs, rats) or both TEC-1 and TEC-2 (mice) antigens. In an indirect immunofluorescence assay, the antigens were found on spermatozoa isolated from caudae epididymides of guinea pigs, rats and Chinese hamsters but not mice. On the other hand, the TEC-2 antigen, which is expressed on mouse eggs, was not detected on eggs from the other species studied. Immunolabeling of epididymal extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that both epididymal antigens have apparent molecular weights of greater than 200,000. In guinea pigs, rats and mice, the antigens were detected by a two-site sandwich radioantibody-binding assay in which the antigen is immobilized and detected with the same antibody; this indicates that several antigenic determinants were present on the same carrier. In mice, some carriers seem to express both TEC-1 and TEC-2 epitopes. In Chinese hamsters, TEC-1 antigen was only detected by the solid-phase assay, suggesting that in this species there are markedly fewer antigenic determinants per carrier molecule. Interspecies differences in the activities of epididymal glycosyltransferases and/or glycosidases appear to be the biochemical mechanism of the species-specific expression of these antigens.
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PMID:Differential expression of mouse embryonic antigens TEC-1 and TEC-2 in the epididymis of four rodent species. 330 64

The serum obtained from an infertile woman induced a specific head-to-head agglutination of human and rat sperm. The immunoglobulin G (IgG) fraction of the serum was obtained and found to interact with the proteins of rat sperm in testis and epididymis. Using an indirect immunofluorescent method with rat sperm from vas deferens, we determined that the antibody recognized the protein on the convex and concave regions of the acrosome and over the entire tail. However, with testicular spermatozoa, the antibody recognized only the distal end of the tails. In paraffin sections of adult rat testis, sperm tails located at the luminal region of the seminiferous tubules stained intensely. Weak but significant staining also occurred on late spermatids. In the epididymal sections, staining was restricted to spermatozoa in the lumen. On the other hand, sections of testes from 25-day-old rats containing spermatogonia and early spermatocytes had a completely negative reaction. Testicular somatic cells, including Sertoli cells, peritubular myoid cells and interstitial cells, did not stain. To identify the testicular protein interacting with the antibody, adult rat testis proteins were prepared and analyzed by a sodium dodecyl sulfate-polyacrylamide gel electrophoretic (SDS-PAGE) immunoblot technique. The antibody interacted with a protein with an estimated molecular weight of 82,000 in the testicular homogenate and particulate fraction, whereas the reaction was considerably weaker with the testicular cytosol fraction.
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PMID:The antibody from an infertile woman that induces sperm agglutination interacts with rat testicular cells and sperm. 331 18

The microheterogeneity of androgen-binding protein (ABP) from rat serum and epididymis was examined by subjecting purified native or deglycosylated preparations to analysis by one- or two-dimensional polyacrylamide gel electrophoresis (PAGE) followed by electrophoretic transfer to nitrocellulose and immunochemical localization. Analysis of native ABP by one-dimensional sodium dodecyl sulfate-PAGE confirmed earlier observations that it is composed of subunits and that the subunits of serum ABP had higher apparent molecular weights than those of epididymal ABP. Treatment with neuraminidase, N-glycanase, or O-glycanase, alone or in combination, resulted in decreases in the apparent molecular weight of the subunits. These analyses indicated that terminal sialic acid residues and Asn-linked oligosaccharides were present on both subunits of ABP from the two sources. The fact that the greatest reduction in the Mr of the heavy subunit occurred following treatment with all three enzymes provides evidence that O-linked sugars are present on it. While enzyme treatment did not result in the appearance of a single subunit, chemical deglycosylation did (Mr 39,600). The carbohydrate composition of the heavy and light subunits of intact serum and epididymal ABP was 22 and 9% and 19 and 8%, respectively. Analysis by two-dimensional PAGE indicated that both subunits of the ABPs were composed of isoelectric variants. Although ABP from the two sources had several variants in common, differences were also observed. Treatment of the ABPs with the enzymes resulted in a shift of the pI values to a more basic pH range, indicating that carbohydrate removal also removed charged moieties. The most dramatic shift in the pI values of the isoforms occurred when O-glycanase was present in the enzyme mixture, providing further evidence for the presence of O-linked oligosaccharides on ABP. Isoelectric variants were present even after chemical deglycosylation of ABP.
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PMID:The microheterogeneity of androgen-binding protein in rat serum and epididymis is due to differences in glycosylation of their subunits. 333 17

This study was initiated to determine whether factors are present in human sperm-free seminal plasma (HSP) that regulate the uptake and release of carnitine from sperm. Bovine caput epididymal sperm cells accumulated more carnitine than caudal sperm cells. A significant reduction in carnitine uptake by caput sperm was observed in the presence of HSP from normal subjects, but not from three subjects with reduced motility. A factor has been isolated from HSP that inhibits carnitine uptake by caput sperm and has the following properties: it is nondialyzable, stable to freeze-thawing, soluble in 60% ammonium sulfate, and has an approximate molecular weight of 158 kd. These data are consistent with the existence of a relatively high molecular weight protein in HSP responsible for the preservation of carnitine concentrations in sperm.
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PMID:A factor in human seminal plasma which affects carnitine accumulation in bovine epididymal sperm. 336 Jan 80

Development of the sperm's capacity to interact with the zona pellucida was investigated at the stage when the acrosome reaction (AR) is induced. The response of epididymal sperm to agents that affect the occurrence of the AR was used to monitor maturational changes. Despite the finding that sperm from the three main epididymal regions were competent to undergo ARs induced by the divalent cation ionophore A23187 (56% AR, 74% AR, and 83% AR in caput, corpus, and cauda, respectively), the cells' responses to solubilized zonae pellucidae were different. When challenged with 5 zonae equivalents/microliter, both corpus and cauda sperm shed their acrosomes in high numbers (75% AR and 86% AR, respectively), whereas caput sperm did not (23% AR). Previous work has shown that the presence of M42 monoclonal antibody (mAb) during in vitro and in vivo fertilization inhibits sperm penetration through the zona pellucida by specific interference with zonae pellucidae-induced ARs. In this study, presence of the M42 mAb did not affect the incidence of A23187-induced ARs, whereas the zona-induced ARs that occurred in both corpus and cauda sperm were inhibited fully with M42 immunoglobulin (Ig) G. In addition, the antigen recognized by M42 mAb on sperm, termed M42 Ag, was examined during epididymal maturation. Although antigen localization appeared indistinguishable by immunofluorescence on sperm taken from the caput, corpus, and cauda regions of the epididymis, modification of this antigen during epididymal transit was detected. Equilibrium-binding studies using 125I-M42 IgG demonstrated a progressive increase during epididymal transit in the amount of M42 mAb that bound to fixed cells. Corpus and cauda sperm bound 185% and 240%, respectively, of the 125I-M42 IgG detected on caput sperm. These changes in expression of M42 Ag paralleled a structural change: the Mr of the antigen decreased from a 195,000/210,000 doublet in caput sperm to a 185,000/200,000 doublet in corpus and cauda sperm, as determined by immunoblot analysis of sodium dodecyl sulfate (SDS)-extracted sperm. Results presented here demonstrate that mouse sperm develop the capacity to undergo a zona-induced AR during epididymal maturation. The M42 antigen, which is involved in the zona-induced AR, is modified during epididymal transit coincident with development of the sperm's responsiveness to zonae. Our working hypothesis, based on these results, is that development of the sperm's capacity to undergo a physiological AR is related to modification of M42 Ag.
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PMID:Epididymal maturation and the acrosome reaction in mouse sperm: response to zona pellucida develops coincident with modification of M42 antigen. 336 70

The presence of caltrin-like proteins in reproductive tract fluid (RTF) and seminal vesicle content from male guinea pigs has been determined. Two fractions with electrophoretic mobility corresponding to Mr = 6200 (main band) and 5100 were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. Isoelectric focusing in thin-layer agarose gels revealed three bands with acidic pIs of 5.3, 6.0, and 6.2, respectively. RTF prevented the enhancement of calcium permeability induced by incubating guinea pig epididymal spermatozoa in medium for capacitation. Spermatozoa incubated for 2 h in minimal culture medium plus pyruvate and lactate containing RTF accumulated less than 30% of the 45Ca2+ accumulated by cells maintained in absence of this fluid. Calcium uptake by preincubated spermatozoa was also inhibited by RTF. Inhibition of calcium transport activity by RTF and seminal vesicle proteins was not decreased by heating the dialyzed preparations at 60 degrees C for 5 min. After this treatment, the inhibitory activity and the protein pattern were stable for 3 wk when stored at 4 degrees C. Unheated extracts lost calcium transport inhibitory activity after 2 or 3 days at 4 degrees C. In spite of the differences in pIs among the proteins from the guinea pig reproductive tract and bovine caltrin, several features indicate they may play a similar role in both species by controlling Ca2+ movement across the plasma membrane. By this mechanism, these proteins could regulate physiologic events essential for the fertilization process.
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PMID:Identification and partial characterization of caltrin-like proteins in the reproductive tract of the guinea pig. 337 81


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