UNIPROT:P56851 - FACTA Search

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

The effect of exercise on the riboflavin status of male rats was studied after 6 or 8 wk of treadmill running. Sedentary and exercised rats were pair fed diets marginal in riboflavin (2.0 or 2.5 mg/kg), and their tissue riboflavin concentrations and erythrocyte glutathione reductase activity coefficients (EGRAC) were compared. The rats exercised for 8 wk had similar body weights but significantly greater weights for heart, gastrocnemius and soleus muscles, less epididymal fat and more total muscle nitrogen and riboflavin than their sedentary controls. Similar changes were evident after 6 wk of exercise, but some were not statistically significant. The EGRAC values of both exercised and sedentary rats responded to changes in dietary riboflavin but were not different from each other. The specific activity of mitochondrial acyl-CoA dehydrogenase (per milligram protein) of the soleus muscle was unaffected by exercise; however, when expressed per gram of tissue or per muscle, the activities in exercised rats were 25% (P less than 0.05) and 60% (P less than 0.01) higher, respectively, than in sedentary rats. On the basis of the riboflavin-dependent parameters measured in this study, exercise did not increase the dietary riboflavin requirement of growing rats but did increase total riboflavin retention in gastrocnemius and soleus muscles.
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PMID:Effect of exercise on riboflavin status of rats. 355 45

As a first step in our study of structure-function relationships among primate and non-primate growth hormones, human growth hormone (hGH) was subjected to the limited digestive activity of human plasmin. The lyophilized whole digest, containing less than 2% of unchanged hormone, had an average of 2.3 new amino-terminal groups per mole. The digest had the same potency as the native hormone (a) in causing weight gain in hypophysectomized rats; (b) in stimulating somatomedin production in hypophysectomized rats; (c) in stimulating upake of [(3)H]leucine into isolated diaphragm of hypophysectomized rats; (d) in accelerating transport of [(14)C]alpha-aminoisobutyric acid into isolated diaphragm of hypophysectomized rats; (e) in stimulating uptake of [3-0-methyl-(14)C]glucose by isolated adipose tissue of hypophysectomized rats; (f) in accelerating conversion of [(14)C]glucose to (14)CO(2) by isolated epididymal adipose tissue of hypophysectomized rats. The digest also caused glucosuria in partially pancreatectomized rats treated with dexamethasone. These metabolic actions of plasmin-digested hGH in the array of animal tests were confirmed by comparable effects elicited in 11 human subjects (nine pituitary-deficient children and adolescents and two nondeficient adults). A single injection of the plasmin digest caused an increase in plasma free fatty acids and a fall in plasma amino acids. Seven daily injections caused positive balances of nitrogen, phosphorous, sodium, and potassium, gain in body weight, and in two of three subjects impairment of glucose tolerance. The potency of the plasmin digest in producing these metabolic effects in man was comparable to that of native hGH.Thus, 2-3 bonds in the hGH molecule can be cleaved by plasmin without impairing the hormone's growthpromoting, anabolic, diabetogenic, and adipokinetic actions for rat and man.
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PMID:Metabolic effects of plasmin digests of human growth hormone in the rat and man. 427 Jun 45

1. Mitochondrial and microsomal fractions of rat epididymal adipose tissue incorporated [1-(14)C]acetyl-CoA equally well into various fatty acids by a chain-elongation mechanism. C(18) and C(20) fatty acids were the two major products, and comprised about 80% of the total fatty acids synthesized in both particles. 2. When incubated in air, mitochondria synthesized stearic acid, octadecenoic acid and eicosamonoenoic acid in almost equal amounts (about 20% each), whereas in microsomal fractions, the synthesis of octadecenoic acid was more than fivefold the stearic acid formation. In both fractions, major components of synthesized monoenoic fatty acids were the Delta(11:12) isomers. Hexadecenoic acid and octadecenoic acid from whole adipose tissue contained approx. 11 and 14% of the Delta(11:12) isomer respectively. 3. When mitochondria or microsomal fractions were incubated in nitrogen, there was increased synthesis of stearic acid and palmitic acid and less of C(16) and C(18) monoenoic acids; synthesis of C(20) acids remained predominantly of the monoenoic acids. Determination of the position of the double bond in the monoenoic acids supported the view that the synthesis of hexadecenoic acid and octadecenoic acid involves a desaturase activity, whereas eicosamonoenoic acid and eicosadienoic acid are formed only by elongation of endogenous fatty acids. 4. Most of the radioactivity was found in free fatty acids (63%) and the phospholipid (26%) fraction. In phospholipids, phosphatidylcholine and phosphatidylethanolamine were the two major components. 5. Most of the fatty acids synthesized, including those not normally found in particle lipids (arachidic acid, eicosamonoenoic acid and eicosadienoic acid) were distributed fairly evenly in the phospholipid and free fatty acid fractions. However, stearic acid was found predominantly in the phospholipid fraction.
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PMID:Synthesis of fatty acids from (1- 14 C)acetyl-coenzyme A in subcellular particles of rat epididymal adipose tissue. 463 95

Plasma membrane vesicles isolated from bovine epididymal and ejaculated spermatozoa have widely different capabilities for transporting Ca2+. Spermatozoa were ruptured by nitrogen cavitation, and the plasma membrane fraction was harvested after low speed and sucrose gradient centrifugation; purity was assessed by marker enzyme analyses, electron microscopy, and sedimentation properties. Plasma membrane vesicles isolated from epididymal sperm accumulate Ca2+ passively at a faster rate and to a greater extent than vesicles prepared from ejaculated sperm. Ca2+ transport across bovine sperm plasma membranes is an ATP-independent, Na+-dependent process that obligatorily exchanges intravesicular Na+ for external Ca2+. The rate of Na+/Ca2+ exchange is significantly lower in ejaculated sperm vesicles than in those of epididymal sperm. Bovine plasma membranes contain little or no Ca2+-dependent ATPase activity. It is suggested that, at the time of ejaculation, calcium flux into bovine sperm is prevented by the interaction of the plasma membrane with putative factors in seminal fluid that specifically interfere with Na+/Ca2+ exchange. We have isolated a protein from seminal plasma that prevents calcium accumulation by bovine epididymal sperm (Rufo, G. A., Jr., Singh, J. P., Babcock, D. F., and Lardy, H. A. (1982) J. Biol. Chem. 257, 4627-4632). A protein with properties resembling those of the seminal calcium transport inhibitor is found on the membrane vesicles from ejaculated sperm but not on membranes from epididymal sperm. We conclude that this protein binds strongly to the plasma membrane of bovine sperm and is responsible for preventing calcium uptake by ejaculated sperm.
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PMID:Regulation of calcium content in bovine spermatozoa. 614 44

Soft tissue injury to one hindlimb of rats was used to test the response to trauma of metabolism in epididymal fat pads. Degradation of [1-14)C]leucine was lower on day 2 after injury, but not on days 1 or 3, whether or not glucose or insulin were provided. Although trauma did not affect the basal rate of release of 14CO2, lactate or pyruvate from fat pads incubated with [U-14C] glucose, the stimulation by insulin of these processes was smaller in fat pads of 2 day traumatized than of normal animals. These results suggest that trauma due to injury may decrease the capacity for utilization of leucine and glucose by adipose tissue. Release of alanine, glutamine and glutamate by fat pads incubated with leucine was also lower on day 2. This decreased efflux could not be accounted for by changes in net protein breakdown or in pyruvate availability and probably reflected their reduced de novo synthesis due to the diminished release of nitrogen from leucine.
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PMID:Metabolism of amino acids, protein and glucose in fat pads of traumatized rats. 637 55

Cytoplasmic droplets of the boar are progressively lost from the flagellum of boar spermatozoa during epididymal transit, at ejaculation and during the nitrogen cavitation technique for isolation of plasma membranes. Apparently very fragile, these structures are broken up in the fluids of the reproductive tract and in the buffer used during the nitrogen cavitation procedure. The maximal potential contamination of cytoplasmic droplet internal vesicular membranes in plasma membrane fractions was determined to be 2.2% of the entire membrane surface area collected. The highly sensitive silver-stained, two-dimensional (2-D) polyacrylamide (PAGE) gels of boar sperm plasma membranes did not reveal cytoplasmic droplet, internal membrane, marker polypeptides, further demonstrating the high purity of plasma membrane preparations. In addition, freeze-fracture demonstrates that the internal membranes of the cytoplasmic droplet show few intramembranous particles and these may contribute little protein to plasma membrane preparations. The presence of two forms of vesicular elements in boar sperm cytoplasmic droplets (typical vesicles and collapsed vesicles) is described.
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PMID:Boar sperm cytoplasmic droplets: their ultrastructure, their numbers in the epididymis and at ejaculation and their removal during isolation of sperm plasma membranes. 646 7

To determine the effects of different levels of glucose intake on glucose homeostasis, gluconeogenesis, body composition, and tumor growth, we gave 8 days of total parenteral feeding of a defined liquid formula diet to groups of Buffalo rats, with and without a transplantable Morris 7777 hepatoma. The level of glucose intake was held at levels which ranged from 0 to 9.5 g/100 body weight per day while the levels of all other nutrients were held constant. Measurements were made on tumor growth rate, terminal blood plasma glucose and whole blood lactate levels, gluconeogenesis, body and organ weight, muscle nitrogen content, liver glycogen, and urine analysis. Tumor-bearing rats (TB) at low glucose intake but not non-tumor-bearing rats (NTB) were found to be dependent on gluconeogenesis for maintenance of blood glucose homeostasis (normoglycemia). Body weight was dependent on glucose intake level in both TB and NTB rats with glucose intake rates of 5.7 g/100 g/day being the point between weight loss or gain. However, under these feeding conditions, tumor growth rate was not dependent on the glucose intake rate. The weight of epididymal fat pad and the size of fat cells were positively correlated with glucose intake rate in both TB and NTB rats, but the fat pad weight in TB rats showed a greater dependence on the rate of glucose intake than it did in the NTB rats. Glucose intake of 3.8 g/100 g/day or less leads to significant loss of muscle mass and loss of muscle nitrogen (protein) in TB but not in NTB rats. Some liver glycogen was detected in all groups of rats except those TB rats with zero glucose intake. TB rats with high glucose intake (5.7 to 9.5 g/100 g/day) had higher blood lactate and lower urine pH than did NTB rats. Thus, TB rats at low glucose intake (3.8 g/100 g/day or less), as opposed to NTB rats, demonstrated a significant dependence on gluconeogenesis for glucose homeostasis, mobilized more of their liver glycogen, and catabolized more of their muscle proteins to supply the increased energy needs of the growing tumor and to maintain normoglycemia.
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PMID:Parenteral level of glucose intake on glucose homeostasis, tumor growth, gluconeogenesis, and body composition in normal and tumor-bearing rats. 661 59

Bovine epididymal spermatozoa were subjected to nitrogen cavitation (600 psi for 10 min) to remove plasma membrane. Examination of the cavitated cells by electron microscopy revealed that the plasma membrane was preferentially removed from the periacrosomal and flagellar regions. Nuclear, mitochondrial and acrosomal membranes remained intact and attached to the spermatozoa, but the cytoplasmic droplets were frequently disrupted and their internal membrane-bound vesicles were released. Lower pressures (less than 200 psi) were relatively ineffective in removing the periacrosomal plasma membrane, while an intermediate pressure (400 psi) removed this membrane from about 70% of the spermatozoa. No apparent selectivity for removal of the periacrosomal and flagellar plasma membrane was observed as a function of cavitation pressure. The cavitated cells were separated from the plasma membranes by differential followed by linear sucrose density gradient centrifugation. Two distinct membrane populations were resolved on sucrose gradients and were designated Band I and Band II. Band I contained only spherical vesicles which arose from the plasma membrane. Surface labeling of intact cells confirmed the plasma membrane as the origin of Band I. The membranes of higher density comprising Band II were heterogeneous consisting of both spherical and flattened vesicles. When purified cytoplasmic droplets were cavitated and centrifuged on the sucrose gradient only Band II was obtained. These studies indicate that nitrogen cavitation of bovine epididymal spermatozoa can result in significant contamination of plasma membrane fractions by cytoplasmic droplet membranes unless appropriate differential centrifugation is used to separate the membrane fractions.
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PMID:Purification and partial characterization of plasma membranes from bovine spermatozoa. 664 46

Polyribosomes from rat epididymal fat pads may be prepared in a synthetically active state and high yield by quick-freezing the tissue in liquid nitrogen, followed by grinding to a frozen powder. The number of initiated (active) ribosomes is limiting in a cell-free protein synthesis assay derived from the frozen preparation that measures completion of nascent polypeptide chains. When starved rats are killed 30 min after a single injection of insulin (0.8 unit, subcutaneously) there is a shift in the ribosomal distribution pattern (on sucrose density gradients) in the direction of larger polyribosomes. This is accompanied by a 2-fold increase in protein synthetic activity of fat cell ribosomes as measured in vitro. When isolated epididymal fat cells are treated with insulin, with or without added glucose, a 2-fold increase in the rate of incorporation of [3H]leucine into [3H]leucine into trichloroacetic acid-insoluble protein is noted within 40 min. The parallel increases in the number of initiated ribosomes, in their synthetic activity in vitro, and in the apparent protein synthetic activity of the whole cell indicate a rapidly evolving action of insulin at the level of peptide chain initiation.
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PMID:Effects of fasting and insulin administration on polyribosome formation in rat epididymal fat cells. 699 69

Some data on the synthesis and characterization of poly(HEMA-MAC) and its applications for fertility control are presented. This new technique involves the use of the polymer, which when injected into the vas deferens lowers the pH sufficiently so as to kill the spermatozoa passing through. The polymer provides an acidic environment for a prolonged time and slowly erodes. The fertility may be restored after complete solubility of the polymer itself over a period of time or by flushing it with a suitable solvent. It is a nonsurgical, nonocclusive, and reversible method of male contraception. In regard to the experimental procedure, copolymerization of HEMA with MAC (35% by weight) in methanol was carried out in a nitrogen atmosphere in glass ampules. Irradiation was performed in a cobalt-60 radiation chamber. All the samples were irradiated at a dose rate of 130 rad/s for a total dose of 0.936 Mrad at room temperature. For studying the spermicidal actions of the copolymer, epididymal fluid from the male rat was collected, diluted 1:10 with Ringer-fructose buffer and microscopically examined. Small swollen pieces of poly(HEMA-MAC) copolymer as well as poly(HEMA) homopolymer were then added to the epididymal fluid and the effect on the spermatozoa was noted. The spermicidal action "in vitro" was indicated by the loss of motility of the spermatozoa immediately on coming in contact with the poly(HEMA-MAC). The spermatozoa remained immotile even after the removal of the copolymer, indicating that they were dead. The polymer treated spermatozoa did not take up any supravital stain confirming that they were killed. This effect was absent only when poly(HEMA) was used. These results clearly show that the spermicidal activity is mainly due to the carboxylic groups of MAC. Possibly the low pH environment due to the ionization of carboxylic groups is responsible for killing the spermatozoa. For all the experiments the injection of the polymeric solution into the vas deferens was given only by exposing the vas deferens, but it is reported that in humans injection into the scrotal wall is possible. The new technique has all the characteristics which can lead to an ideal contraceptive method. Preliminary results of "in vitro" experiments on human spermatozoa with these hydrogels are encouraging.
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PMID:Novel mode of contraception using polymeric hydrogels. I. 705 60

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