Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A histochemical study has been made of the localization and changes of lipids, carbohydrates, ATPase and 5'-nucleotidase in fresh and fixed frozen sections of testicular and epididymal components in the normal and alpha-chlorohydrin-treated rats. After treatment with a single low dose of alpha-chlorohydrin, the phospholipids are decreased with corresponding increase in triglycerides in both the testis and epididymis. Glycogen, ATPase and 5'-nucleotidase are also decreased after treatment with alpha-chlorohydrin. The physiological significance of these histochemical changes has been discussed.
 ...
PMID:Histochemical changes of the rat testis and epididymis after treatment of alpha-chlorohydrin-effects of a single low dose. 15 90

The effect of dietary fats on phospholipid class distribution and fatty acid composition was studied in rat fat cell plasma membrane. Three groups of male Wistar weanling rats were fed for 8 wk three diets differing in the amount and nature of the fats: 1.5% sunflower oil (low fat control; LFC), 10% sunflower oil (high fat, unsaturated; HFU), 1.5% sunflower oil + 8.5% cocoa butter (high fat, saturated; HFS). Plasma membranes were prepared from epididymal adipocytes. The amount and type of dietary fat significantly altered membrane phospholipid distribution. Phospholipid content was lowered with HFU as compared to LFC or HFS diets, but no changes were observed for cholesterol. Phosphatidylinositol (PI) and phosphatidylserine (PS) were less affected by dietary changes than were other phospholipid classes. Major changes were detected for phosphatidylcholine (PC), phosphatidylethanolamine (PE) and sphingomyelin (SM) contents. No large changes in PC and PE fatty acid compositions were observed between the LFC and HFS groups, but the HFU diet induced several changes. Correlations with plasma membrane 5'-nucleotidase activities are discussed.
 ...
PMID:Effect of dietary fat on phospholipid class distribution and fatty acid composition in rat fat cell plasma membrane. 235 53

The acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was examined in male C57BL/6J mice differing only at the Ah locus. Wild type mice (Ahb/b, "b/b") were treated once with 0, 50, 100, 200, 300, and 400 micrograms TCDD/kg po while congenic mice (Ahd/d, "d/d") received a single dose of 0, 400, 800, 1600, 2400, and 3200 micrograms TCDD/kg. Mice were checked daily, weighed twice a week, and those that survived, killed 35 days post-treatment. The LD50 values were 159 and 3351 micrograms/kg for b/b and d/d mice, respectively. Mean time to death was 22 days and was independent of dose and genotype. Decrease in body weight gain was noted in both strains 5 days after treatment and occurred at doses greater than or equal to 100 micrograms/kg in b/b mice and 1600 micrograms/kg in d/d mice. Dose-related increases in liver weight (both absolute and relative to body weight) and decreases in thymus, spleen, testes, and epididymal fat pad weights were observed at 8-24-fold higher doses in d/d than in b/b mice. A dose-related increase in segmented neutrophils was observed in both strains. Serum chemistry values indicated that 8-24X greater doses of TCDD were needed to elevate sorbitol dehydrogenase, alanine aminotransferase, and 5'-nucleotidase and to decrease total and esterified cholesterol in d/d than in b/b mice. Few effects were seen on total bile acids, serum triglycerides, glucose, or nonesterified cholesterol. In the liver, hepatocellular cytomegaly, fatty change, and bile duct hyperplasia occurred in both strains in a dose-related manner, as did thymic and splenic atrophy. Necrosis of germinal epithelium in the testes and edema in the stomach submucosa occurred at acutely toxic doses. These lesions also occurred at doses 8-24X greater in d/d than in b/b mice. Thus, the spectrum of toxicity is independent of the allele at the Ah locus, but the relative dose needed to bring about various acute responses is approximately 8-24X greater in congenic mice homozygous for the "d" allele than for the wild type animals carrying two copies of the "b" gene.
 ...
PMID:Differential toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in C57BL/6J mice congenic at the Ah Locus. 237 98

1. Adipocytes were isolated from epididymal white fat and interscapular brown fat of male rats, and activities of 5'-nucleotidase, adenosine deaminase and adenosine kinase were measured in cell extracts. 2. 5'-Nucleotidase activity in white adipocytes was increased in streptozotocin-diabetes, decreased in hypothyroidism and increased with age. That activity in brown adipocytes was unchanged in diabetes, decreased in hypothyroidism and increased with age. 5'-Nucleotidase activity was higher in white adipocytes from female rats. 3. Adenosine deaminase activity in white adipocytes was increased in diabetes, decreased in hypothyroidism and increased with age. That activity in brown adipocytes was decreased in diabetes and hypothyroidism. 4. Adenosine kinase activity in both cell types was unchanged in diabetes or hypothyroidism, but increased with age.
 ...
PMID:Enzymes involved in adenosine metabolism in rat white and brown adipocytes. Effects of streptozotocin-diabetes, hypothyroidism, age and sex differences. 282 32

The enzymes of adenosine metabolism were investigated in suspensions of epididymal mouse spermatozoa incubated under conditions which support capacitation in vitro. High levels of adenosine deaminase activity were found in sperm suspensions, but the enzyme was located in the surrounding medium and was not intrinsic to spermatozoa. 5'-Nucleotidase was also present in the surrounding medium while in sperm cells it existed as an ecto-enzyme. Adenosine was not metabolized by washed spermatozoa under conditions used for the assay of adenosine deaminase or adenosine kinase, but it was metabolized rapidly by unwashed sperm suspensions. Incubation of sperm suspensions in conditions which modulate fertilizing ability resulted in small alterations in intrinsic 5'-nucleotidase activity of spermatozoa. In contrast, the activity of adenosine deaminase was not consistently modulated by such manipulations. Adenosine deaminase and 5'-nucleotidase exhibited similar kinetic parameters to enzymes from other sources and their activities were inhibited by coformycin and alpha, beta-methylene adenosine 5'-diphosphate, respectively. These studies highlight the low adenosine-metabolizing ability of spermatozoa coupled with the extensive metabolism in the medium which surrounds them. Extracellular adenosine metabolism can therefore occur and may modulate capacitation in vitro.
 ...
PMID:Enzymes of adenosine metabolism in mouse sperm suspensions. 284 Apr 94

Cyclic AMP has been implicated as a regulator of capacitation, but the control of its metabolism in sperm remains obscure. A recent study of mouse sperm has shown capacitation-related changes in the activities of both adenylate cyclase, which increased during incubation, and cyclic nucleotide phosphodiesterase, which decreased. The present study was conducted to extend these observations by measuring phosphodiesterase activity in sperm incubated in media with modified calcium and/or glucose content, conditions known to modulate fertilizing ability. Phosphodiesterase activity of sequential sperm samples, taken first when sperm are essentially uncapacitated and then when they are either partially or completely capacitated, decreased with time under all conditions, and in each case the greater fall in activity was seen in the medium that would support the greater change in fertilizing ability of the sperm population. Sperm washed by centrifugation to remove epididymal fluid also displayed a reduction in phosphodiesterase activity with time. The medium surrounding the sperm contained about half of the total phosphodiesterase activity, as well as 5'-nucleotidase and adenosine deaminase. The crude enzyme preparation showed complex kinetic behavior when assayed over a range of cAMP concentrations, but the reduction in activity with time was seen at all substrate levels. The observed changes in phosphodiesterase activity, together with the increased adenylate cyclase activity seen under these sperm incubation conditions, would increase cAMP availability with time, thus providing further evidence for a fundamental role for cAMP in controlling the events of capacitation.
 ...
PMID:Phosphodiesterase activity of mouse sperm incubated under conditions that modulate fertilizing potential in vitro. 285 27

Sperm maturation and storage occur in a unique milieu created in large part by the epididymal epithelium. To learn more about the interaction of the epididymal epithelial cell with both luminal and systemic environments, we now report on the preparation and characterization of epididymal epithelial cell plasma membranes. A preparation enriched for epididymal epithelial cell plasma membranes was isolated from collagenase-digested epididymal tubule fragments by hand-Dounce homogenization, differential centrifugation, and sucrose gradient centrifugation. The final membrane fraction was enriched 11-fold for the plasma membrane marker 5'-nucleotidase; 2.6-fold for the lysosomal marker acid phosphatase, and 3-fold for the Golgi marker thiamine pyrophosphatase. No enrichment was observed for mitochondrial or endoplasmic reticulum enzyme markers. Specific and saturable transferrin-binding activity was also detected in the final preparation. Electron microscopy revealed the presence of vesicles and sheets of membranes as well as an occasional Golgi apparatus. The plasma membrane fraction was used to generate monoclonal antibodies. Of 102 wells exhibiting growth, 12 were positive by immunofluorescent staining of frozen sections. Ten of these recognized determinants in epithelial cells, and 2 stained peritubular smooth muscle cells. Most of the epithelial cell-specific antibodies stained brush border alone or in combination with the basolateral plasma membrane. Three antibodies stained the Golgi apparatus. Most antibodies were specific for particular epididymal regions, 3 also recognized determinants in the kidney, and 1 stained residual bodies in the testis.
 ...
PMID:Isolation and characterization of epididymal epithelial cell plasma membranes. 336 69

Plasma membranes of boar sperm from caput, corpus and cauda of the epididymis were purified by differential- and sucrose-density equilibrium centrifugation and were found to yield a single band at a density of 1.13 g/cm3. This fraction was enriched in acid and alkaline phosphatase, 5'-nucleotidase and (Na+ + K+)-ATPase activities, whereas it contained minimal amounts of hyaluronidase and N-acetylglucosaminidase and no succinic acid dehydrogenase activities. The plasma membrane of caput, corpus and cauda sperm had the same phospholipid/protein and cholesterol/phospholipid ratios but yielded different amounts of protein and individual lipid classes. Several changes in the plasma membrane were observed during transit of sperm through the epididymis. Within the phospholipid class a decrease in the percentage of phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol was detected accompanied by an increase in amount of phosphatidylcholine, sphingomyelin and polyphosphoinositides. In the other lipid classes there was a decrease in the amount of free fatty acid and the major glycolipid. The amount of cholesterol decreased, while the amount of desmosterol and cholesterol sulfate increased. There was an increase in the amount of diacylglycerol. In addition, the changes in the fatty acid composition of the total membrane lipid and each phospholipid were determined. The above changes in the lipid composition of the plasma membrane during epididymal maturation may help to explain the decreased resistance to cold shock and changes in membrane fluidity of sperm during transit in the epididymis.
 ...
PMID:Changes in the lipid content of boar sperm plasma membranes during epididymal maturation. 399 37

1. A rapid method was developed for the preparation of plasma membranes from either isolated rat fat-cells or intact epididymal fat-pads with the use of density-gradient centrifugation in the presence of Percoll. On the basis of 5'-nucleotidase activity, the yield of plasma membranes was about 50% and purification over 10-fold. Activities of marker enzymes indicated that contamination by mitochondria and microsomal fraction was small. 2. Incorporation of 32Pi into proteins associated with plasma membranes within isolated fat-cells was investigated. Four major bands of labelled phosphoproteins were separated by sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis; the apparent subunit mol.wts. were 67 000, 61 000, 26 000 and 20 000. None of these phosphoprotein bands corresponded to periodate/Schiff-staining glycoproteins. The extent of phosphorylation of the 61 000 mol.wt phosphoprotein band was increased by about 30 and 60% after exposure of fat-cells for 15 min to insulin or adrenaline respectively.
 ...
PMID:Use of a novel rapid preparation of fat-cell plasma membranes employing Percoll to investigate the effects of insulin and adrenaline on membrane protein phosphorylation within intact fat-cells. 626 55

The glucose transport mechanism of rat epididymal fat cells was reconstituted into egg lecithin liposomes, and their carrier-mediated transport activity ws estimated from the difference in the rates of uptake of D-[3H]glucose and L-[14C]glucose. Insulin increased the glucose transport activity in the plasma membrane-rich fraction while decreasing the activity in the Golgi-rich fraction in agreement with our previous data (Suzuki, K., and Kono, T. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 2542-2545). The development of the insulin effects was inhibited when cells were exposed to 2,4-dinitrophenol or KCN before the insulin treatment. In addition, the reversal of the insulin effects was blocked upon exposure of insulin-treated cells to 2,4-dinitrophenol or KCN prior to the elimination of the hormone. In contrast, neither development nor reversal of the insulin effects was affected by cycloheximide or puromycin. The temperature coefficients of the transport activities reconstituted from the basal or insulin-treated forms of the plasma membrane-rich or Golgi-rich fractions were all identical. The recoveries of protein, 5'-nucleotidase, UDP-galactose:N-acetylglucosamine galactosyltransferase, and NADH dehydrogenase into subcellular fractions were determined. However, net effects of insulin on the glucose transport activities have remained unknown for lack of an appropriate marker enzyme of the Golgi-like vesicles associated with the transport activity. It is suggested that the glucose transport mechanism is recycled between the plasma membrane-rich and Golgi-rich fractions by an energy-dependent reaction.
 ...
PMID:Energy-dependent and protein synthesis-independent recycling of the insulin-sensitive glucose transport mechanism in fat cells. 701 68


1 2 Next >>