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)

Efferent reproductive ducts of male mice, including ductuli efferentes, epididymis, and vas deferens, were fixed and embedded in paraffin, and sections were stained with a battery of lectin-horseradish peroxidase conjugates to localize specific sugars or sugar sequences in glycoconjugates. Cilia and the apical surfaces of ciliated cells in the ductuli efferentes stained intensely with lectin specific for sialic acid and terminal alpha-N-acetyl-D-galactosamine. Flask cells and clear cells in the epididymis reacted positively and similarly with most lectins used, providing evidence that these cell types are related. In contrast, disparities in lectin staining suggest that flask cells and clear cells are a cell type distinct from principal cells. Basal cells were not present in the ductuli efferentes but formed a continuous layer in the epididymis and vas deferens. Basal cells contained oligosaccharides terminated by sialic acid and alpha-D-galactose and varying amounts of terminal beta-D-galactose and alpha-N-acetyl-D-galactosamine. Basal cells also stained variably with lectins specific for the core region of complex type N-glycosidic side chains. The basal cells varied structurally, having long spinous apical processes approaching or reaching the lumen in region I of the epididymis and being low cuboidal or squamoid and lacking apical processes in epididymal regions II-V and in the vas deferens. The contiguous nature of the basal cells and the presence of glycoconjugates bearing terminal alpha-galactosyl residues in all basal cells suggest a possible role for these cells in a regulatory influence on transepithelial movement of fluid and/or ions in the epididymis and vas deferens.
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PMID:Histochemical evaluation of glycoconjugates in the male reproductive tract with lectin-horseradish peroxidase conjugates: II. Staining of ciliated cells, basal cells, flask cells, and clear cells in the mouse. 382 61

Ram cauda epididymal spermatozoa were incubated for 10 min at 34 degrees C with or without 1.0 mM-RS-alpha-chlorohydrin before (1) 5 mM-D-glucose or (2) 10 mM-L-lactate plus 1 mM pyruvate or (3) 5 mM-D-glucose plus 10 mM-L-lactate plus 1 mM-pyruvate or (4) no substrate was added. Without alpha-chlorohydrin, the motility, the ATP concentration and the energy charge of the spermatozoa were maintained for 240 min by substrate combinations 1-3 but with no added substrate (4) the motility declined after 60 min. All the values decreased dramatically after 10 min in spermatozoa exposed to alpha-chlorohydrin in substrate conditions 1 and 3 (glucose present) but alpha-chlorohydrin had no significant effect in conditions 2 and 4 (no glucose) except after prolonged incubation. In a dose-response experiment glucose-dependent ATP dissipation began to occur with 0.025 mM-RS-alpha-chlorohydrin. A similar effect was seen in boar spermatozoa exposed to 0.1-5.0 mM-alpha-chlorohydrin and 5 mM-D-glucose. With boar spermatozoa the presence of 10 mM-L-lactate and 1 mM-pyruvate as well as glucose prevented the loss of ATP. We conclude that this concerted action of alpha-chlorohydrin and glucose is probably responsible for the contraceptive action of alpha-chlorohydrin and propose that it may depend on 'futile substrate cycling' in the glycolytic pathway.
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PMID:The presence of glucose increases the lethal effect of alpha-chlorohydrin on ram and boar spermatozoa in vitro. 396 53

Immobilin, the highly viscoelastic glycoprotein isolated from rat cauda epididymal fluid, exhibits all of the key biochemical characteristics of a mucin: 1) it has a very high molecular weight (will not pass through a 10(6) dalton cut-off filter; 2) it contains 56% carbohydrate, with low or undetectable levels of mannose, xylose and uronic acid; 3) the carbohydrates (primarily galactose, N-acetylglucosamine and N-acetylgalactosamine) are arranged in short, oligosaccharide chains (4-20 monosaccharides per chain); 4) these oligosaccharide chains can be cleaved by NaOH in the presence of NaBH4, suggesting O-glycosidic linkages; and 5) the protein core is pronase-resistant. Immobilin, however, contains no detectable sialic acid, and 67% of the oligosaccharides are uncharged, indicating that immobilin is less acidic than most other mucins.
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PMID:Rat cauda epididymal fluid is a mucus. 405 30

To determine sequential surface glycoprotein changes in ram spermatozoa during epididymal maturation, labeling procedures were used that were specific for galactosyl, galactosaminyl, and sialyl residues. Spermatozoa and fluids were collected from the rete testis through surgically inserted catheters or flushed from the lumen of selected regions of the epididymis: i.e., caput, proximal and distal corpus, and cauda epididymidis. Ejaculated spermatozoa were collected by electrical stimulation. Electrophorectic analysis of galactose (GAO)-sodium boro[3H]hydride (NaB3H4)-treated spermatozoa revealed a sharp overall decrease in carbohydrate residue labeling during sperm transport through the efferent ducts and caput epididymidis, whereas several high molecular weight components in the 600K to 250K zone persisted throughout epididymal transit. Preincubation of spermatozoa with neuraminidase (NEUA) exposed galactose residues that had not been labeled with GAO alone (i.e., 97K, 43K, 24K) in both cauda epididymal and ejaculated spermatozoa. Treatment with sodium metaperiodate-NaB3H4 labeled many of the surface components displayed by NEUA-GAO-treated spermatozoa and revealed an overall shift in sialyl residue labeling from high molecular weight components in immature testicular spermatozoa to low molecular weight components in mature cells. The labeling procedures applied allowed only a qualitative interpretation of the results and they presumably represent the minimum possible changes. Nonetheless, our results demonstrate that glycoproteins are a major factor in surface transformations of ram spermatozoa in the epididymis, especially during the initial stages of maturation.
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PMID:Glycoproteins: a variable factor in surface transformation of ram spermatozoa during epididymal transit. 406 38

We have used perifusion organ culture of proximal and distal caput epididymal tubules of the rat to study the secretion of proteins by epididymal epithelium and uptake of the luminal radioactive proteins by sperm. The amount of incorporation of L-[35S]methionine into luminal fluid proteins was time dependent and completely inhibited by cycloheximide. The association of labeled proteins with cultured sperm was also dependent on time and continuous, with sperm still acquiring labeled luminal proteins after protein synthesis was arrested. A Mr = 46,000 molecule was found to be heavily labeled in luminal fluid and sperm extracts. Fluorograms of all L-[35S]methionine extracts immunoprecipitated using an antiepididymal alpha-lactalbumin antibody (Klinefelter and Hamilton, 1984) showed labeling of an Mr = 18,000 molecule and, in addition, the Mr = 46,000 molecule, but immunostaining was specific only for the Mr = 18,000 molecule and the heavy chain of the immunoglobulin. We suggest that the Mr = 46,000 molecule may be galactosyltransferase. Galactose oxidase-NaB[3H]4 labeling of the cultured caput sperm cell surface revealed a Mr = 23,000 molecule that was able to be immunoprecipitated with antiepididymal alpha-lactalbumin antibody. Our data suggest that this cell surface molecule is similar to one component of the fluid epididymal alpha-lactalbumin-like complex and, in addition, show that glycosylation of the sperm surface can occur in the caput epididymidis.
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PMID:Synthesis and secretion of proteins by perifused caput epididymal tubules, and association of secreted proteins with spermatozoa. 408 28

Six specific agglutinins were used to identify the terminal sugar residues in the surface oligosaccharides of rabbit and hamster spermatozoa by specific agglutination. Species differences in epididymal sperm were found in the terminal residues, resembling alpha-D-mannose, D-galactose, N-acetyl-D-glucosamine, and N-acetyl-D-galactosamine. Species similarities were found in terminal residues, resembling L-fucose and N-acetylneuraminic acid. When ejaculated rabbit sperm were compared to epididyimal sperm, the latter were more agglutinable with a specific agglutinin recognizing N-acetyl-D-glucosamine.
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PMID:Terminal saccharides on sperm plasma membranes: identification by specific agglutinins. 504 Oct 26

The rat epididymis is known to produce and secrete glycoproteins which interact with spermatozoa during the maturation process. The synthesis of the protein core of these compounds is dependent on androgenic stimulation. As a consequence, we studied the possible androgenic control of the N-glycosylation process dependent on the dolichol (Dol) pathway. Glucosyl and mannosyl transferase activities in rat epididymal microsomes decreased by approximately 76% after only 2 days of castration with respect to intact controls. Depleted mannosyl transferase activity could be restored to control values by administration of 100 micrograms/day testosterone propionate (TP) for 4 days. The effect of 20 micrograms/day TP was blocked by the simultaneous administration of 500 micrograms/day of the antiandrogen cyproterone acetate. The addition of excess dolichyl phosphate (12 times the Michaelis-Menten constant (Km) value) to the incubation mixture did not eliminate the difference in mannosyltransferase activity between epididymal microsomes from castrated rats and these from control or testosterone-treated animals. Moreover, the endogenous pool of dolichyl phosphate was found unchanged in the different hormonal situations. Finally, the incorporation of [14C]mannose into lipid-bound oligosaccharides and into glycoproteins was decreased by approximately 60% as a result of castration and reinduced to control values by treatment with TP (50 micrograms/day for 4 days). The results demonstrate the androgen dependence of the initial steps of N-glycosylation in the rat epididymis and suggest that the hormonal regulation is exerted at the level of Dol-nucleotide sugar transferases, rather than upon the size of the endogenous Dol phosphate pool.
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PMID:Androgen dependence of protein N-glycosylation in rat epididymis. 623 Nov 79

The concentration of glucose in the plasma of alloxan-diabetic rats was 23.4 +/- 0.86 mM (mean +/- SEM; n = 18), and the concentration of insulin was 11.4 +/- 1.67 microU/ml (mean +/- SEM; n = 17). The weights of the ventral prostate (0.45 +/- 0.03 vs. 0.72 +/- 0.04 g) and seminal vesicles (1.23 +/- 0.06 vs. 1.84 +/- 0.08 g) were decreased compared to control values and the rats lost body weight, but the weights of the testes were not significantly different from control values (3.14 +/- 0.08 vs. 3.23 +/- 0.14 g/pair). Similar changes were seen in streptozotocin-diabetic rats. The concentration of fructose (micromoles per g fresh wt) was greater in the coagulating gland of alloxan-diabetic (19.6 +/- 1.3; n = 17) than control rats (9.1 +/- 0.7; n = 18). The production of 14CO2 from D-[U-14C]glucose by spermatozoa or seminiferous tubules from diabetic rats was decreased compared to that in controls [28 +/- 3 vs. 53 +/- 6 nmol glucose converted/10(8) spermatozoa X 30 min (n = 8) and 0.81 +/- 0.03 vs. 1.08 +/- 0.03 mumol glucose converted/g fresh wt X 30 min (n = 7)]. There was no change in the production of lactate or 3HOH from D-[2-3H] glucose, and the presence of insulin (10 mU/ml) in the incubation had little effect. Rat epididymal spermatozoa took up 2-deoxy-D-glucose by a facilitated diffusion mechanism; the Km was about 0.2 mM, with a maximum velocity of about 0.10 nmol/10(6) spermatozoa X 10 sec. Neither alloxan-diabetes nor the presence of insulin (10 mU/ml) had an appreciable effect on these parameters.
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PMID:The effect of experimentally induced diabetes on the metabolism of glucose by seminiferous tubules and epididymal spermatozoa from the rat. 623 7

Pieces of rat epididymal fat tissue were maintained in a biochemically defined medium for 20 to 44 hours in either the absence or presence of a sulfonylurea at levels known to be effective in humans. Prolonged exposure of adipocytes to sulfonylureas did not influence the number of insulin receptors or their affinity to insulin or the ability of insulin to induce receptor loss (down-regulation). Also, the sulfonylureas did not influence the basal uptake of the D-glucose analogs 2-deoxyglucose and 3-O-methylglucose. However, exposure to these drugs resulted in a potentiation of the stimulatory effects of insulin on hexose transport at submaximal and maximally effective concentrations of insulin. The average potentiation was approximately 30%. In addition, sulfonylureas enhanced stimulation of hexose uptake by the insulin mimickers, hydrogen peroxide and vitamin K5. These oxidants are known to manifest insulin-like actions subsequent to insulin binding. Under conditions in which glucose transport was rate limiting, the conversion of glucose to carbon dioxide and the total lipids mirrored the findings of hexose uptake. However, at a glucose concentration of 50 mM, at which hexose transport is no longer rate limiting, sulfonylureas did not potentiate metabolism in th absence or presence of insulin. These results may help to explain the hypoglycemic action of the drug in view of the recent finding that a postreceptor deficit is present in noninsulin-dependent diabetes mellitus.
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PMID:Extrapancreatic effects of sulfonylureas. Potentiation of insulin action through post-binding mechanisms. 640 22

Fractionation of testicular, epididymal, and serum extracts containing rat androgen-binding protein (rABP) on a Concanavalin A-Sepharose (Con A) column resolved two peaks of immunoreactive protein. The first peak was present in the void volume, and the other was bound by the column and specifically eluted by alpha-methyl-D-glucoside. These two peaks of immunoreactive rABP have been designated form I and form II for the portions of rABP that do not and do bind, respectively, to Concanavalin A. In the course of studying this heterogeneity, we observed that the distribution of the two forms of rABP was the same in the blood and cytosols prepared from testis and epididymis of young rats before the formation of the blood-testis barrier; that is, the ratio of form I to form II ranged from 1:1 to 1:2. Similar heterogeneity was observed in extracts of the reproductive tract from mature animals. However, the blood of adult rats contained reduced amounts of form I relative to form II, so that their ratio was about 1:5. Subsequent studies of infertile rats heterozygous for the Hre gene (Hre/ +), in which total rABP secretion was decreased, and of their normal littermates, indicated that the reduced amount of form I ABP in the sera of mature rats is typical of adult animals regardless of strain or genetic abnormality. The reduced amount of form I relative to form II observed in the blood of adult rats could result from either reduced secretion or increased metabolic clearance of form I in the blood compartment. To distinguish between these possibilities, the blood clearance of the two forms was estimated after orchiectomy. The disappearance rate of form I was not significantly different from that of either form II or unfractionated serum. These results are consistent with reduced release into blood of form I relative to form II rABP rather than increased clearance of form I in adult animals.
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PMID:The heterogeneity of rat androgen-binding protein in serum differs from that in testis and epididymis. 653 76


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