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)

Human chorionic somatomammotropin extracted and purified from placenta at term was proved to have a lipolytic action in the epididymal fat pad of rats. The following mechanism appears to be involved in the lipolytic action of the hormone; human chorionic somatomammotropin activates adenyl cyclase, thereby increasing the concentration of cyclic AMP in the tissue, which, in turn, activates protein kinase to lead to the activation of hormone sensitive lipase.
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PMID:Lipolytic action of human chorionic somatomammotropin. 16 57

Clomiphene (10(-3) - 10(-2) M) in a dose-dependent manner inhibited the lypolytic response of isolated rat epididymal adipose tissue and fat cells to epinephrine, ACTH, and dibutyryl-cyclic AMP. Furthermore, it reduced the non-hormonally stimulated activity of a crude preparation of lipase from epididymal adipose tissue. The accumulation of cyclic AMP produced by epinephrine in fat cells was not prevented by clomiphene at a concentration causing antilipolytic activity. It is concluded from these results that clomiphene unlike most other antilipolytic drugs exerts its antilipolytic effect by an inhibition of the lipase rather than by inhibition of adenylcyclase.
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PMID:Evaluation of the antilipolytic action of clomiphene in vitro. 17 45

Starvation did not cause increase of hormone-sensitive lipase in rat epididymal adipose tissue. Adrenaline did not activate lipase in the fat cells, although it accelerated the release of free fatty acids from the cells. The results suggest that the mechanism of the stimulation of lipolysis by adrenaline is different from that in the cyclic AMP theory. Adrenaline-sensitive fat globules were prepared by hypotonic treatment of fat cells. Lipolysis in the fat globules was stimulated by adrenaline. It was shown that adrenaline-induced lipolysis in the fat globules was not due to activation of lipase but to initiation of a reaction between lipase and triglyceride. It is well known that calcium ions are essential for ACTH-induced lipolysis and that the hormone stimulates calcium uptake into adipose tissue. It was demonstrated that calcium ions accelerated formation of a complex between fat and lipase. The mechanism of the actions of adrenaline and ACTH are discussed on the basis of these results.
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PMID:Mechanism of actions of adrenaline and ACTH in fat mobilization. 17 4

The reversible deactivation of chicken adipose tissue hormone-sensitive lipase alpha(previously activated with Mg2+ ATP and adenosine 3':5'-monophosphate) required Mg2+ and was inhibited by phosphate. These results are consistent with the assumption that deactivation of the protein kinase-activated enzyme is catalyzed by a lipase phosphatase. Cholesterol ester is catalyzed by a lipase phosphatase. Cholesterol ester hydrolase similarly was activated and reversibly deactivated. The activity of endogenous lipase phosphatase in pH 5.2 precipitate fractions was reduced, and in some cases eliminated, by incubation at 50 degrees for 20 min in buffer containing 20% glycerol. Heating at 50 degrees greatly increased the apparent percentage activation of triglyceride and cholesterol ester hydrolases but this was due to a selective decrease in basal (nonactivated) hydrolase activities. Essentially all endogenous lipase phosphatase could be removed by treatment of the pH 5.2 precipitate fraction with ATP-Sepharose affinity gel. The addition of a partially purified preparation of rat liver phosphorylase phosphatase deactivated triglyceride and cholesterol ester hydrolases. The deactivation process was concentration, 5 mM) and was inhibited by 5 mM phosphate and by phosphorylase alpha. Reversible deactivation of hormone-sensitive lipase alpha was also observed with crude prepa- and by phosphorylase alpha. Reversible deactivation of hormone-sensitive lipas alpha was also observed with crude preparations of phosphoprotein phosphatases from rat and turkey hearts, and from rat epididymal fat pads. Thus, hormone-sensitive lipase is deactivated by a variety of phosphoprotein phosphatases from different tissues and different species, implying a low degree of specificity for the deactivating system.
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PMID:Role of phosphoprotein phosphatases in reversible deactivation of chicken adipose tissue hormone-sensitive lipase. 19 Feb 35

Subfractionation of the fat free homogenate of rat adipose tissue showed that a high yield of triglyceride lipase was recovered reproducibly in the microsomal supernatant fraction (cytosol) when rat epididymal fat pads were homogenized in sucrose-EDTA-Tris medium. Triglyceride lipase was bound on heparin-Sepharose. Hydrolyzing activity towards triacylglycerol was eluted as a single, sharp peak in 0.7 M NaCl, 5 mM sodium barbital and 20% glycerol (pH 7.0). The triglyceride lipase was not inhibited by 1 M NaCl and not stimulated by the presence of fresh human serum. A lipoprotein-lipase activity was demonstrable in the cytosol when adipose tissue from fed rats were used. Fasting of the animals lowered this activity.
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PMID:Affinity chromatography on heparin-sepharose of rat adipose tissue triglyceride lipase from cytosol. 66 59

The lipoprotein lipase (clearing-factor lipase) activity of the white adipose tissue from rats aged between 1 and 145 days was determined. Five adipose-tissue sites (epididymal, uterine, subcutaneous, perirenal and intramuscular) together with serum concentrations of triacylglycerol, cholesterol and glucose were studied. The pattern of enzyme-activity change was remarkably similar in all the sites studied, although the growth of the tissues proceeded non-uniformly. After a peak of activity early in suckling, lipoprotein lipase activity fell to low values by 20 days of age. At weaning (21 days) the activity increased sharply and within 5 days high values were regained. The serum triacylglycerol and cholesterol concentrations were low at birth and reached peaks of concentration coincidentally with the minima of white-adipose-tissue lipoprotein lipase activities, seen late in suckling. The changes in enzyme activity were related to other metabolic changes in adipose tissue and with the known changes in plasma insulin concentrations occurring during development.
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PMID:Changes in the lipoprotein lipase (clearing-factor lipase) activity of white adipose tissue during development of the rat. 66 49

The chemical and biochemical properties of cholesterol-enriched and cholesterol-poor chylomicrons from rat lymph have been compared. The enriched particles, prepared from cholesterol-containing lipid dispersions, passed into the duodenum, had four to ten times the cholesteryl ester content of the control chylomicrons but had the same content of total "core" (cholesteryl ester + triglyceride) lipid. Both chylomicron species had the same protein composition, the same phospholipid composition, and the same composition of triglyceride fatty acids. The rate of hydrolysis of chylomicron triglyceride for enriched and control particles was determined using both soluble and membrane-supported lipoprotein lipase (LPL) species from heart and adipose tissues. The lipase that was functional in the isolated perfused heart showed no significant difference in initial catabolic rate with cholesterol-enriched and control chylomicrons. The same result was obtained with this isolated LPL species in vitro. The lipase that was functional in isolated perfused epididymal adipose tissue showed a slightly lower catabolic rate with cholesterol-enriched particles (84% of that obtained with control chylomicrons). The same result was obtained with isolated adipose tissue LPL. It is concluded that cholesteryl ester content of chylomicrons under these conditions neither affects their protein composition nor has a major effect on their rate of reaction with lipoprotein lipase.
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PMID:Metabolism of cholesterol-enriched chylomicrons. Catabolism of triglyceride by lipoprotein lipase of perfused heart and adipose tissues. 69 May 10

1. When fat-cells are isolated from the epididymal adipose tissue of 24h-starved rats and incubated at 25 degrees C in the presence of dialysed serum, glucose, insulin, amino acids and heparin, the total clearing-factor lipase acitivity of the incubation system increases progressively over a period of several hours. 2. All of the increase in activity is accounted for by the appearance of enzyme in the appearance of enzyme in the incubation medium and the fat-cell activity does not change significantly. Cycloheximids, at a concentration that prevents protein synthesis, does not affect the appearance of enzyme in the incubation medium, but the fat-cell enzyme activity is decreased in its presence. 3. The magnitude of the increase in total clearing factor lipase activity is unaffected by the omission of heparin from the medium. However, less enzyme is extracted in tis absence and the fat-cell activity increases. Cycloheximide again only affects the rise in cell activity and does not alter the activity in the incubation medium. 4. When serum in the incubation medium is replaced by casein, the distribution of enzyme between the cells and the medium is changed, but the magnitudes of the increases in total enzyme activity are similar. 5. These characteristics of the clearing-factor lipase response of isolated fat-cells differ in several respects from those observed earlier with intact adipose tissue from 24h-starved rats (Robinson & Wing, 1971; Cryer et al., 1973). The differences could be due, in part, to changes in the relative amounts of two different molecular forms of the enzyme that occur during the isolation of the fat-cells.
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PMID:The clearing-factor lipase activity of isolated fat-cells. 80 20

Vibrio cholerae enterotoxin stimulates lipolysis in rat epididymal fat cell suspensions. Like hormones this toxin increases adenylate cyclase activity, raising levels of cyclic adenosine 3',5'-monophosphate (cAMP), which activates a cellular lipase. Using specific blocking agents, we studied the responses to the adrenergic lipolytic hormones epinephrine, norepinephrine, and isoproterenol, and to cholera toxin. All stimulators were used at 100 x threshold dose. Propranolol (34 muM), a beta blocking agent, inhibited epinephrine stimulation (P less than 0.001) but not that of toxin (P greater than 0.2). Choleragenoid (25 mug/ml), a natural toxoid of cholera toxin, blocked stimulation by toxin (P less than 0.001) but not that of the adrenergic agents (P greater than 0.2). A beta blocker, practolol (3 mM), inhibited stimulation by the catecholamines tested (P less than 0.005) but not that of toxin (P greater than 0.05). Higher concentrations of propranolol (340 muM) and the alpha blocking agents phenoxybenzamine (3 mM) and phentolamine (1.6 mM) inhibited all agonists (P less than 0.001). The response to theophylline was inhibited by all blockers (P less than 0.05) except propranolol at the lower concentration (34 muM). A combined beta and alpha blockade using propranolol and epinephrine together did not inhibit toxin-mediated lipolysis. It appears that stimulation by cholera toxin is independent of beta adrenergic receptors. A major inhibition of theophylline-mediated lipolysis by alpha blocking drugs indicated a nonspecific effect of these agents at the concentrations used. The uninhibited response to toxin in the presence of propranolol and epinephrine suggests a lack of relationship of the toxin receptor to either alpha or beta receptors.
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PMID:Selective inhibition of cholera toxin- and catecholamine-stimulated lipolysis by blocking agents. 119 34

Experiments were carried out to elucidate the mechanism of triglyceride accumulation in epidiymal adipose tissue of obese mice made by goldthioglucose injection. Specifically, fat mobilization and its deposition were investigated. In goldthioglucose-treated mice, the weight of the epididymal adipose tissue was 1,200 percent of that of control mice, while adrenaline-induced lipolysis and lipase activity of the tissue were 272 and 450 percent of control respectively. These results suggest that deposition of fat far exceeds fat mobilizing activity in the adipose tissue of the obese mice. It was found that triglyceride synthesis from glucose increased in the adipose tissue of these mice. Therefore, it is suggested that obesity in gold thioglucose-treated mice may not be due to decrease in fat mobilization but to increase in triglyceride synthesis from carbohydrate.
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PMID:Triglyceride metabolism in epididymal adipose tissue of obese animals. 122 94


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