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)

A new aminosugar named nojirimycin B (1) has been isolated as its bisulfite adduct from the culture broth of Streptomyces lavendulae SF-425, together with nojirimycin. Microbiological oxidation of 1 with Gluconobacter suboxydans IAM 1829 gave a delta-lactam (2). The structures of 1 and 2 were determined to be 5-amino-5-deoxy-D-mannopyranose and D-mannonic-delta-lactam, respectively, on the basis of 1H NMR spectroscopy and X-ray structural analysis. Both 1 and 2 exhibited powerful inhibitory activity against rat epididymal alpha-mannosidase and apricot beta-glucosidase.
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PMID:Novel glycosidase inhibitors, nojirimycin B and D-mannonic-delta-lactam. Isolation, structure determination and biological property. 654 15

Studies were performed in male hamsters to determine whether antiluminal, active glucose transport played a role in maintaining low glucose concentrations in male reproductive tract fluids. Studies of tissue uptake of 3H-3-O-methyl-D-glucose (3H-3OMG) demonstrated that after equilibrium seminiferous tissue 3H-3OMG concentrations were similar to blood plasma concentrations. Previous studies have shown that under similar circumstances seminiferous tubule lumen fluid 3H-3OMG concentrations are much lower than blood plasma concentrations. These facts suggested the possible presence of an antiluminal, active transport system for glucose in the seminiferous epithelium. In vivo perfusion of seminiferous tubules with fluids containing 3H-3OMG demonstrated an approximately 80% removal of the isotope after 1.5 hours. This movement was against a blood-lumen glucose gradient and was consistent with antiluminal active glucose transport. Increasing phloridzin concentrations in intraluminal perfusion fluid tended to be associated with decreased removal of 3H-3OMG from the lumen fluid; however, this effect was not significant; thus the evidence failed to support a hypothesis of an active antiluminal glucose pump in the seminiferous epithelium. Movement of 3H-3OMG across the cauda epididymidal epithelium was limited in both the pro- and antiluminal direction. The blood-epididymal barrier for 3H-3OMG movement appears to be much more restrictive than the blood-seminiferous tubule barrier for the same molecule.
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PMID:The transepithelial movement of 3H-3-O-methyl-D-glucose in the hamster seminiferous and cauda epididymidal tubules. 661 17

Studies using genetic and biochemical probes have suggested that mouse sperm surface galactosyltransferases may participate during fertilization by binding N- acetylglucosamine (GlcNAc) residues in the egg zona pellucida. In light of these results, we examined sperm surface galactosyltransferase activity during in vitro capacitation to determine whether changes in enzymatic activity correlated with fertilizing ability. Results show that surface galactosyltransferases on uncapacitated sperm was preferentially loaded with poly N-acetyllactosamine substrates. As a consequence of capacitation in Ca(++)-containing medium, these polylactosaminyl substrates are spontaneously released from the sperm surface, thereby exposing the sperm galactosyltransferase for binding to the zona pellucida. Sperm capacitation can be mimicked, in the absence of Ca(++), either by washing sperm in Ca(++)-free medium, or by pretreating sperm with antiserum that reacts with the galactosyltransferase substrate. In both instances, sperm galgactosylation of endogenous polylactosaminyl substrates is reduced, coincident with increased galactosylation of exogenous GlcNAc, and increased binding to the zona pellucida. Binding of capacitated sperm to the egg can be inhibited by pronase-digested high molecular weight polyactosaminyl glycoside extracted from epidymal fluids or from undifferentiated F9 embryonal carninoma cells. Thus, these glycosides function as "decapacitation factors" when added back to in vitro fertilization assays. These glycoside "decapacitation factors" inhibit sperm-egg binding by competeing for the sperm surface galactosyltransferase, since (a) they are galactosylated by sperm in the presence of UDP[(3)H]galactose, and (b) enzymatic removal of terminal GlcNAc residues reduces "decapacitation factio" competition. On the other hand "conventional" low molecular weight glycosides, isolated from either epididymal fluid or differentiated F9 cells, fail to inhibit capacitated sperm binding to the zona pellucida. These results define a molecular mechanism for one aspect of sperm capacitation, and help explain why removal of "decapacitation factos" is a necessary prerequisite for sperm binding to the zona pellucida.
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PMID:Sperm surface galactosyltransferase activities during in vitro capacitation. 681 11

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

A rabbit antibody to mouse 3T3 cell fibronectin was used in conjunction with a fluorescein-tagged second antibody to detect fibronectin-like activity on the surface of rabbit spermatozoa. Only ejaculated sperm displayed an intense and highly localized fluorescence over the acrosomal region. Cauda epididymal sperm of the rabbit as well as several other species did not exhibit any reaction. The fluorescent activity could be eliminated by trypsin treatment but was re-established by incubation in cell-free seminal fluid. Sperm recovered from females 10-12 h after mating showed a reduction or absence of antifibronectin fluorescence, suggesting that this component's loss could be a factor in sperm capacitation. Because fibronectins show strong binding to collagen, mixtures of ejaculated sperm and collagen were examined in the light and electron microscope. Living sperm appear to have a strong affinity for collagen and quickly adhere to the filaments by their heads, while continuing vigorous flagellations. Surface labeling of sperm with the galactose-oxidase-NaB[3H]4 technique, extraction with urea-detergent mixtures and affinity chromatography of extracts on gelatin-Sepharose revealed a single radioactive band of mot wt approximately 40,000 after SDS polyacrylamide gel electrophoresis and fluorography.
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PMID:A collagen-binding protein on the surface of ejaculated rabbit spermatozoa. 699 66

Autoantibodies raised in guinea pigs (GP) by hyperimmunization with epididymal sperm recognize antigens present on the plasma membrane of intact sperm and antigens associated with acrosome-reacted sperm. Plasma membrane autoantigens were characterized by SDS-PAGE analysis of immune precipitates from detergent extracts of radiolabeled epididymal sperm. Three major protein bands with approximate molecular weights (MW) of 69,000, 62,000 and 40,000 daltons were exhibited. Galactose oxidase and periodate oxidation followed by tritiation revealed two major plasma membrane glycoprotein autoantigens with MWs of 35,000 and 32,000 daltons and one sialoglycoprotein of 34,000 daltons. Antigenic molecules of similar MW were also detected by autoantisera to guinea pig testicular homogenates. Immune precipitates of radiolabeled detergent extracts of acrosome-reacted sperm analyzed by SDS-PAGE exhibited two major carbohydrate-containing peaks, one with a MW of approximately 42,000 daltons and one of 6,000 daltons. Since the 6,000 dalton peak was immunoprecipitated from the organic phase of both chloroform:methanol 2:1 and n-butanol extracts, the antigen may be a glycolipid. The possible existence of glycolipid autoantigen in GP sperm was further supported by the reaction in a solid phase radioimmunoassay of autoantibodies to GP sperm with glycolipid extracts from GP testis. This study demonstrates the presence of multiple autoantigenic specificities in the sperm-plasma membrane, acrosome-reacted sperm and testis of guinea pigs. It also demonstrates for the first time glycolipid autoantigens in testis and sperm.
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PMID:Immunochemical analysis of guinea pig sperm autoantigens. 703 3

Hamster eggs with postovulatory oviduct contents were added to a simple defined medium, without serum albumin, but supplemented with different combinations of energy sources. They were then inseminated by epididymal spermatozoa. In a medium containing D-glucose but without pyruvate and/or lactate, high proportions of acrosome-reacted spermatozoa (78-94%) and eggs undergoing fertilization (89-96%) were obtained 9-9.5 h after insemination. With only pyruvate or lactate as substrates, or with both pyruvate and lactate, acrosome reactions occurred in only 2-4% of the sperm. When D-glucose ranging in concentration from 2.78 to 8.34 mM was added, a high proportion (82-95%) of the eggs inseminated were found to be fertilized. Substituting D-galactose, L-glucose, L-fucose, D-lactose, or D-saccharose for D-glucose resulted in very low numbers of acrosome-reacted sperm (0-12%) and fertilized eggs (0-7%). However, in the presence of metabolizable sugars, such as D-mannose or D-fructose, the acrosome reaction was seen in 78-85% of the sperm examined and 87-95% of the eggs tested were fertilized.
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PMID:The importance of the presence of metabolizable sugars in a medium for in vitro fertilization of hamster eggs with postovulatory oviduct contents. 707 70

The in vivo movement of [3H] 3-0-methyl-D-glucose ([3H] 30MG), [3H] L-glucose, [3H] inositol and [3H] alpha-aminoisobutyric acid ([3H] alpha AIB) into and across the rat testicular and epididymal epithelium was investigated. After systemic infusion of [3H] 30MG, both epididymal and testicular tissue concentrations of the isotope were approximately 50% lower than blood plasma levels, even 24 h after infusion. Similar results were observed for caput and seminiferous tubule fluid. There was a significant reduction of [3H] 30MG caput lumen to blood ratio when the blood glucose concentration was increased to 2-5 times that of normal. A similar reduction of [3H] 30MG caput lumen to blood ratio was observed when 1000 mumol of 2-methylaminoisobutyric acid (meAIB) was infused with the isotope. Caput luminal [3H] L-glucose concentration never exceeded 10% of blood levels. The data suggest that glucose is transported across the testicular and epididymal epithelium via a facilitated diffusion mechanism (carrier mediated) and that the carrier is situated on the basolateral membrane. This study did not demonstrate either a glucose countertransport system or a glucose-inositol exchange system across the epithelium of the caput epididymidis. Epididymal tissue (except cauda) and caput luminal fluid concentrations of [3H] inositol exceeded that of blood plasma within 1 h after infusion of isotope. The proximal regions of the epididymis demonstrated significantly higher transporting activity than either cauda or testis. Systemic infusion of 100 mumol myo-inositol significantly reduced the transport of [3H] inositol into caput luminal fluid and epididymal and testicular tissue. It is suggested that there is a carrier situated on the basolateral membrane which is able to transport inositol against a concentration gradient (probably active transport). Epididymal tissue (except cauda), testicular tissue and caput luminal fluid concentrations of [3H] alpha AIB also exceeded that of blood plasma but only 24 h after infusion of isotope. The initial segment and corpus regions of the epididymis had a significantly higher transporting activity compared to the remainder of the epididymis and the testis. A dose of 500 mumol meAIB reduced epididymal uptake of [3H] alpha AIB. These results suggest that there is a carrier situated in the basolateral membrane which can transport the amino acid against a concentration gradient (probably active transport). The differences in transport activities of the compounds investigated along the reproductive tract probably indicate differences in the affinity or quantity of the carriers. These epididymal transporting systems regulate the movement of material across its epithelium and may help to protect the epididymis from fluctuations in the blood concentration of each compound.
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PMID:Rat testis and epididymis can transport [3H] 3-O-methyl-D-glucose, [3H] inositol and [3H] alpha-aminoisobutyric acid across its epithelia in vivo. 715 62

Previous results demonstrated that androgen-dependent rat specific epididymal proteins (SEP) were bound to spermatozoa during their maturation in the epididymis. This paper describes the purification of glycoprotein DE, which constitutes 40% of SEP, and the identification and semiquantitative determination of the sugars forming its oligosaccharide chain. Affinity chromatography on Sepharose-Concanavalin A produced a sample of D-E 95% pure in which 10.5 g of sugar were present per 100 g protein. The percentual composition of the oligosaccharide was D-mannose 19%; D-galactose 3%; N-acetyl-D-glucosamine 33%; N-acetyl-neuraminic acid 31% and D-glucose 13%.
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PMID:Carbohydrate composition of specific rat epididymal protein. 716 Sep 23

The investigation demonstrated a restriction of [3H]3-O-methyl-D-glucose ([3H]3-OMG) net transport into seminiferous tubule fluid. Net transport of [3H]3-OMG into the cauda epididymidal tubule was even more limited. By 4 months after vasectomy, there was no statistical difference in the net transport of the isotope into the seminiferous tubule fluid, but there was a significant increase in net transport into cauda epididymidal fluid. These results demonstrate that the blood-epididymal barrier can be even more restrictive to molecular transport than the blood-testis barrier and that vasectomy can have subtle effects on characteristics of molecular transport in the cauda epididymidis.
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PMID:[3H]3-O-methyl-D-glucose transport from blood into the lumina of the seminiferous and epididymal tubules in intact and vasectomized hamsters. 743 37


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