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 lipoprotein lipase activity in adipose tissue of Sprague-Dawley rats 1, 4, 9 and 15 months of age, was investigated. The study revealed that a significant inverse relationship exists between serum triglyceride level and lipoprotein lipase activity in epididymal fat pad. Thus, the lipoprotein lipase activity in 1 and 15 months old rats are on the average 5.3 and 1.1 nkat/g wet weight, respectively, simultaneously as serum triglyceride level increase from 0.74 mmol/l to 3.51 mmol/l, respectively. It is suggested that impaired removal of very low density lipoproteins is one possible explanation of the enhanced levels of this lipoproteins in the old rat. The lipase activity investigated had the characteristic properties of lipoprotein lipase, i.e. it was activated by the addition of serum, inhibited by high ionic strength and varied with the nutritional state. However, it could not be exclude that monoacylglycerol lipase present in epididymal fat pad also decreased with age. The possible connection between the age-related reduction of lipoprotein lipase activity in epididymal fat pad and the age-related gomerulonephritis found in these rats is discussed.
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PMID:Lipoprotein lipase activity in adipose tissue of spontaneously hyperlipidemic rats. 719 33

Triglyceride-rich lipoproteins (chylomicrons and very low density lipoproteins) were labelled "in vivo" by injecting (U-14C)-glycerol and (9-10(n)-3H)-palmitate in female rats. After purification, these lipoproteins contained most of the 3H in esterified fatty acids and the 14C in glyceride glycerol of neutral lipids. This preparation was incubated "in vitro" in the presence of either isolated adipocytes or epididymal fat pad pieces from male rats. With the incubation, a certain proportion of both 3H-esterified fatty acids and 14C-glyceride glycerol disappeared from the medium, the effect being greater when the incubations were performed with adipocytes than with fat pad pieces. Much greater radioactivity appeared in the lipids of adipocytes than in those of fat pad pieces at the end of 60 or 120 min incubation, and the incorporation of 3H being relatively greater than that of 14C. With the latter isotope, the label appeared not only in the glyceride glycerol fraction but also in the free and esterified fatty acids. Although it is known that lipoproteins lipase activity is lower in adipocytes than in fat pad pieces, our results indicate that, in the former preparation, the enzyme may be more accessible for the substrate. These data also demonstrate that glycerol released by the hydrolysis of lipoprotein glycerides may be partially incorporated into lipids by adipose tissue.
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PMID:"In Vitro" utilization of labelled esterified fatty acids and glyceride glycerol from triglyceride-rich lipoproteins in rat adipose tissue. 726 35

The influence of intestinal microflora and aging on the lipid metabolism in germ-free (GF) and conventional (CV) rats, 8 and 40 weeks old, was investigated. Serum cholesterol at the age of 8 and 40 weeks and serum triglyceride (TG) at the age of 40 weeks was higher in GF than in CV rats. Serum cholesterol decreased and serum TG and corticosterone tended to increase in both GF and CV rats with aging. In the rats 40 weeks of age, lipase activity of the pancreas and the duodenal, jejunal, and colorectal contents in GF rats increased, but that of the ileal and cecal contents in GF and CV rats decreased. Intestinal microflora tended to depress the age-related increase of serum TG and lipase activity of the pancreas and the duodenal and jejunal contents. Lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) activities of the epididymal adipose tissue were higher in CV than in GF rats at both 8 to 40 weeks of age. The LPL activity increased and the HSL activity decreased in both GF and CV rats with aging. The concentration of cholesterol increased and that of bile acids decreased in the cecal contents of 40-week-old GF rats.
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PMID:Intestinal microflora and aging: age-related change of lipid metabolism in germ-free and conventional rats. 726 76

The effect of dietary octacosanol, a long-chain alcohol, on lipid metabolism was investigated in rats fed on a high-fat diet for 20 d. The addition of octacosanol (10 g/kg diet) to the high-fat diet led to a significant reduction (P < 0.05) in the perirenal adipose tissue weight without decrease of the cell number, suggesting that octacosanol may suppress lipid accumulation in this tissue, whereas no effect was seen in the epididymal adipose tissue weight and in the lipid content in liver. Octacosanol supplementation decreased the serum triacylglycerol concentration, and enhanced the concentration of serum fatty acids, probably through inhibition of hepatic phosphatidate phosphohydrolase (EC 3.1.3.4). Though the activity of hormone-sensitive lipase (EC 3.1.1.3) was not influenced by octacosanol, higher activities of lipoprotein lipase (EC 3.1.1.34) in the perirenal adipose tissue and the total oxidation rate of fatty acid in muscle were observed. Lipid absorption was not affected by the inclusion of octacosanol. Thus, the present results suggest that the dietary incorporation of octacosanol into a high-fat diet affects some aspects of lipid metabolism.
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PMID:Octacosanol affects lipid metabolism in rats fed on a high-fat diet. 776 66

Hypertriglyceridemia is common in chronic renal failure (CRF); this derangement is due to decreased peripheral removal of triglycerides. Certain data indicate that the state of secondary hyperparathyroidism of CRF is, at least in part, responsible for derangements in lipid metabolism. It has been proposed that chronic excess of parathyroid hormone exerts its deleterious effects on many organs through its ability to raise basal levels of cytosolic calcium. Prevention of the latter by a calcium channel blocker is followed by the correction of organ dysfunctions. The present study examined the effect of treatment of CRF rats with verapamil on several parameters of lipid metabolism. Chronic renal failure rats displayed hypertriglyceridemia, fat intolerance, reduced postheparin plasma lipoprotein and hepatic lipase activities, decreased hepatic lipase in liver homogenate, and elevated calcium content in liver and epididymal fat. Treatment of the CRF rats with verapamil prevented all these derangements in lipid metabolism. These effects of verapamil were similar to those produced by parathyroidectomy of CRF rats. The data are consistent with the formulation that chronic excess of parathyroid hormone increases the calcium burden of liver and adipose tissue and consequently impairs the synthesis and/or release of lipoprotein and hepatic lipases. Reduced availability of these enzymes in plasma results in impared peripheral removal of triglycerides, leading to hypertriglyceridemia.
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PMID:Verapamil prevents chronic renal failure-induced abnormalities in lipid metabolism. 832 79

The effect of ephedrine (E) and theophylline (T), administered alone and in combination (E/T), on weight loss, resting energy expenditure and post-heparin lipoprotein lipase activity in plasma (PHLA) and in adipose tissue (ATLP) were investigated in obese over-fed rats, who had been diet restricted (-40% of normal caloric intake) for three weeks. E, T and E/T significantly increased weight loss in all experimental groups as compared to the controls. Weight loss was achieved not only by preventing the adaptive fall in resting energy expenditure associated with diet restriction, but by raising it above basal level. The effect of E/T mixture was no greater than that of E or T alone. E, T and E/T administration increased PHLA in plasma while hypocaloric diet alone did not influence the activity of the enzyme. ATLP in the epididymal fat pads decreased insignificantly in all experimental groups, as well as in the controls. Serum cholesterol levels were not influenced by hypocaloric diet and by drug administration, but serum triglycerides increased significantly in E, T and E/T treated groups. The elevation of PHLA after ephedrine and/or theophylline administration was mostly due to an increase in the hepatic lipase (HL) level. This enzyme contributes to the removal of the atherogenic intermediate density lipoproteins from blood serum. The increased HL activity in drug-treated, diet-restricted obese rats may therefore play a role in the prevention of atherosclerosis.
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PMID:Effect of ephedrine and theophylline on weight loss, resting energy expenditure and lipoprotein lipase activity in obese over-fed rats. 839

1. The mechanism of contraction to noradrenaline (pEC50 5.6 +/- 0.1) in the rat epididymal vas deferens (mediated via alpha 1A-adrenoceptors) has been studied in functional experiments. 2. Contractions to noradrenaline at 10(-6) M were potentiated by the diacylglycerol (DAG) kinase inhibitor R 59022 (3 x 10(-7) M) from 49 +/- 4% to 63 +/- 3% maximum response and the time taken from initiation of contraction to the maximum response was reduced from 16 +/- 2 s to 9 +/- 1 s. The same contractions were not significantly potentiated by the DAG lipase inhibitor, U-57,908, 10(-5) M (51 +/- 2% control and 53 +/- 4% in the presence of U-57,908) nor was the time taken from initiation of contraction to the maximum response significantly altered (17 +/- 1 s control and 16 +/- 1 s in the presence of U-57,908). 3. Concentration-dependent contractions to noradrenaline (NA) were reduced by staurosporine (10(-7) M) and the selective protein kinase C inhibitor, calphostin C (10(-6) M) from 68 +/- 2% (NA, 3 x 10(-6) M) to 28 +/- 2% and 20 +/- 2% respectively and from 94 +/- 2% (NA, 3 x 10(-5) M) to 50 +/- 2% and 44 +/- 2% respectively. Contractions to K+ (40 +/- 2% maximum response to NA) were also significantly reduced by staurosporine (10(-7) M) (35 +/- 2%) but not by calphostin C (43 +/- 3%). 4. The phorbol ester, phorbol-12,13-dibutyrate (PDBu), produced a phasic, concentration-dependent contraction (10(-7) M - 10(-4) M) which was 41 +/- 2% of the maximum response to NA at 10(-4) M PDBu. The contraction to PDBu (10(-5) M) was reduced by calphostin C (10(-6) M) from 33 +/- 5% to 4 +/- 1% maximum response to NA. 5. Non-cumulative contractions to NA (10(-8) M - 10(-4) M) were abolished in Ca(2+)-free Krebs solution containing EGTA (1 mM) and were reduced in the presence of nifedipine (10(-6)M) in normal Krebs solution by 91 +/- 2% at 10(-4)M NA. The contraction to PDBu (10(-5)M, 33 +/- 5% maximum response to NA) was also abolished in Ca(2+)-free Krebs solution containing EGTA (1 mM) or by the presence of nifedipine (10(-6)M) in normal Krebs solution. 6. When NA (10(-4)M) was added to vasa deferentia in Ca(2+)-free Krebs solution containing EGTA (1 mM), following its wash out (and with EGTA later removed from the Krebs solution), readdition of Ca2+ (2.5 mM) to the Krebs solution produced no response. Cyclopiazonic acid (10(-5)M), which can deplete Ca2+ from intracellular stores, also produced no contraction. Therefore influx of extracellular Ca2+ is not a consequence of depletion of intracellular Ca2+ stores (capacitative Ca2+ influx). 7. Pre-incubation of tissues for 30 min with either cyclopiazonic acid (10(-5)M) or ryanodine (10(-4)M), which can both deplete intracellular Ca2+ stores, did not reduce the contractions to NA (3 x 10(-6)M). Pre-incubation of vasa deferentia with cyclopiazonic acid (1 or 3 min, when any rise in [Ca2+]i produced by cyclopiazonic acid might still exist) did not potentiate the contraction to PDBu (10(-5)M). Thus mobilization of intracellular Ca2+ may not be required for the activation of protein kinase C involved in these contractions. 8. In conclusion, the contraction of the rat epididymal vas deferens to NA mediated by alpha 1A-adrenoceptors appears to depend upon activation of protein kinase C by diacylglycerol, resulting in the influx of extracellular Ca2+ through voltage-gated Ca2+ channels. There was no evidence for a role of inositol trisphosphate in the contraction to noradrenaline in this tissue.
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PMID:The role of diacylglycerol and activation of protein kinase C in alpha 1A-adrenoceptor-mediated contraction to noradrenaline of rat isolated epididymal vas deferens. 882 67

Guinea pig intestinal phospholipase B is a calcium-independent phospholipase hydrolyzing sequentially the acyl ester bonds at sn-2 and sn-1 positions of glycerophospholipids, promoting the formation of sn-glycero-3-phosphocholine from phosphatidylcholine. This 140-kDa glycoprotein from the brush border membrane of differentiated enterocytes contributes to lipid digestion as an ectoenzyme. The cDNA coding for guinea pig phospholipase B was revealed to be the homologue of AdRab-B, an mRNA appearing in rabbit upon intestine development. The sequence predicts a polypeptide of 1463 amino acids displaying four homologous repeats, two of them containing the lipase consensus sequence GXSXG. A 5-kilobase transcript was particularly abundant in mature ileal and jejunal enterocytes but was also detected in epididymis, where phospholipase B displayed a higher molecular mass (170 kDa versus 140 kDa in intestine), with no obvious evidence for enzyme activity. Trypsin treatment of phospholipase B immunoprecipitated from epididymal membranes reduced its size to 140 kDa, coinciding with the appearance of a significant phospholipase A2 activity. The same results were obtained in COS cells transfected with phospholipase B cDNA. Since sn-glycero-3-phosphocholine present at high concentrations in seminal plasma mainly stems from epididymis, this suggests a possible role of phospholipase B in male reproduction. This novel localization also unravels a mechanism of phospholipase B activation by limited proteolysis involving either trypsin in the intestinal lumen or a trypsin-like endopeptidase in the male reproductive tract.
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PMID:Ectopic epididymal expression of guinea pig intestinal phospholipase B. Possible role in sperm maturation and activation by limited proteolytic digestion. 959 72

Although intermediate metabolism is known to follow circadian rhythms, little information is available on the variations in lipoprotein lipase (LPL) and hepatic lipase (HL) activities during the 24-h period, and there is also a lack of adequate statistical analysis. Here, adult male rats were fed ad libitum and kept at 21 degrees C under 12:12-h light-dark cycles. They were killed in batches every 3 h over a 24-h period. Lipase activities were determined in plasma and fresh homogenates of epididymal white adipose tissue (EWAT), interscapular brown adipose tissue (IBAT), heart, skeletal muscle, and liver. Plasma insulin, corticosterone, glucose, triacylglycerol (TAG), cholesterol, glycerol, beta-hydroxybutyrate, and liver and muscle glycogen were determined. Cosinor analysis was used to evaluate the presence (significance of fit of cosine curve to data and variance explained by rhythm) and characteristics of possible circadian rhythms [acrophase (phi), mesor, and amplitude]. Statistically significant circadian rhythms were detected for 1) all metabolites studied, except TAG, cholesterol, and liver HL activity; 2) LPL and HL activity in plasma (both phi in light phase); and 3) LPL activity in all tissues studied (phi: heart in light phase; skeletal muscle, IBAT, and EWAT in dark phase). Liver also showed a circadian rhythm of LPL activity, with phi near that in plasma. These findings demonstrate for the first time that, in physiological conditions, LPL activities in plasma and various tissues, including liver, and HL activity in plasma follow circadian rhythms. Their metabolic significance is discussed.
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PMID:Circadian rhythms of lipoprotein lipase and hepatic lipase activities in intermediate metabolism of adult rat. 972 79

The enzymic regulation of triacylglycerol breakdown in skeletal muscle is poorly understood. Western blotting of muscle fibres isolated by collagenase treatment or after freeze-drying demonstrated the presence of immunoreactive hormone-sensitive lipase (HSL), with the concentrations in soleus and diaphragm being more than four times the concentrations in extensor digitorum longus and epitrochlearis muscles. Neutral lipase activity determined under conditions optimal for HSL varied directly with immunoreactivity. Expressed relative to triacylglycerol content, neutral lipase activity in soleus muscle was about 10 times that in epididymal adipose tissue. In incubated soleus muscle, both neutral lipase activity against triacylglycerol (but not against a diacylglycerol analogue) and glycogen phosphorylase activity increased in response to adrenaline (epinephrine). The lipase activation was completely inhibited by anti-HSL antibody and by propranolol. The effect of adrenaline could be mimicked by incubation of crude supernatant from control muscle with the catalytic subunit of cAMP-dependent protein kinase, while no effect of the kinase subunit was seen with supernatant from adrenaline-treated muscle. The results indicate that HSL is present in skeletal muscle and is stimulated by adrenaline via beta-adrenergic activation of cAMP-dependent protein kinase. The concentration of HSL is higher in oxidative than in glycolytic muscle, and the enzyme is activated in parallel with glycogen phosphorylase.
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PMID:Expression of hormone-sensitive lipase and its regulation by adrenaline in skeletal muscle. 1033 90

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