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)

Increases in the amount of the active non-phosphorylated form of pyruvate dehydrogenase in rat epididymal adipose tissue, as a result of incubation with insulin, persist not only during the preparation of mitochondria but also during subsequent incubation of coupled mitochondria in the presence of respiratory substrates. No effect on insulin was found if the hormone was added directly to mitochondria in the presence or absence of added plasma membranes. Concentrations of several possible regulators of pyruvate dehydrogenase kinase (ATP, ADP, NADH, NAD+, acetyl-CoA, CoA and potassium) were measured in rat epididymal-adipose-tissue mitochondria incubated under conditions where differences in pyruvate dehydrogenase activity persist as a result of insulin action. No alterations were found, and it is suggested that inhibition of the kinase is not the principal means by which insulin activates pyruvate dehydrogenase. The intramitochondrial concentration of magnesium was also unaffected. Differences in pyruvate dehydrogenase activity in interscapular brown adipose tissue associated with manipulation of plasma insulin concentrations of cold-adapted rats were also shown to persist during the preparation and subsequent incubation of mitochondria in the presence or absence of GDP. It is pointed out that the persistence of the effect of insulin on pyruvate dehydrogenase in incubated mitochondria will facilitate the recognition of the mechanism of this action of the hormone. Evidence that the short-term action of insulin involves an increase in pyruvate dehydrogenase phosphate phosphatase activity rather than inhibition of that of pyruvate dehydrogenase kinase is discussed.
 ...
PMID:Persistence of the effect of insulin on pyruvate dehydrogenase activity in rat white and brown adipose tissue during the preparation and subsequent incubation of mitochondria. 632 Aug 7

Synthesis of fatty acids was measured in the liver and in epididymal adipose tissue of sand rats and albino rats. In chow-fed sand rats the rate of hepatic lipogenesis, as measured by the incorporation of 3H2O into fatty acids, was four- to sevenfold higher than in albino rats and in sand rats on a low-calorie saltbush diet. The contribution of [14C]glucose to lipogenesis in sand rat liver was lower than in albino rats. In fed sand rats lipogenesis incorporating 3H2O was stimulated by casein but not by glucose. In adipose tissue, lipogenesis measured 1 h after administration of 3H2O was much lower in sand rats than in albino rats. In vitro incorporation of [14C]glucose or acetate into adipose tissue fatty acids was negligible. In adipose tissue, uptake of very-low-density lipoproteins (VLDL) and lipoprotein lipase activity were sevenfold higher than in albino rats. Activities of NADP-malate dehydrogenase, acetyl CoA carboxylase, and fatty acid synthetase were considerably higher in the liver of chow-fed sand rats than in albino rats. It was concluded that obesity in sand rats originates from hepatic lipogenesis without a significant contribution of local fatty acid synthesis in adipose tissue.
 ...
PMID:Lipogenesis in the sand rat (Psammomys obesus). 634 15

Atherosclerotic lesions were formed in the aorta of rats given a high cholesterol diet containing propylthiouracil (PTU) and vitamin D2 (atherogenic diet) for 8 weeks. The effects of niceritrol (pentaerythritol tetranicotinate), which lower the plasma lipid level, on lipid metabolism in the arterial wall of the atherosclerotic rats were studied. Niceritrol significantly decreased the plasma cholesterol level of atherosclerotic rats, which was 823 mg/100 ml, or about ten times that of control rats. On treatment with niceritrol, the cholesterol level was reduced most in the very low density lipoprotein (VLDL) fraction (d less than 1.006). Heparin-releasable lipoprotein lipase activity in epididymal adipose tissue, lipoprotein lipase activity in post-heparin plasma, and VLDL-triolein hydrolyzing activity in adipose tissue stromal vessels were all higher in niceritrol-treated atherosclerotic rats. Of the enzymes in the arterial wall concerned with cholesterol ester metabolism, acid cholesterol esterase activity was decreased in atherosclerotic rats, while niceritrol treatment increased this activity. The ratio of acyl-CoA cholesterol acyltransferase activity (ACAT) to neutral cholesterol esterase activity was higher in atherosclerotic rats than in control rats, but was lower in niceritrol-treated rats than in atherosclerotic rats. From these results, it is concluded that niceritrol modifies enzyme activities in such a way as to reduce the cholesterol ester content of the arterial wall and lower plasma VLDL and LDL cholesterol levels.
 ...
PMID:Effect of niceritrol on lipid metabolism of aorta in atherosclerotic rats. 647 52

Atherosclerotic lesions formed in the aorta of rats given diet containing propylthiouracil (PTU), vitamin D2 and high cholesterol diet (atherogenic) for 8 weeks. The effect of clinofibrate, which lowers the plasma lipid level, on lipid metabolism in the arterial wall of the atherosclerotic rats was studied. Clinofibrate significantly decreased the high plasma cholesterol level of atherosclerotic rats, which was 823 +/- 256 (mean +/- SD) mg/dl, or about ten times that of control rats (85 +/- 11 mg/dl). On treatment with clinofibrate, the cholesterol level was reduced most in the very low density lipoprotein (VLDL) fraction (d less than 1.006). Heparin-releasable lipoprotein lipase activity in epididymal adipose tissue, lipoprotein lipase activity in post heparin plasma, and VLDL-triolein hydrolizing activity in adipose tissue stromal vessels were higher in clinofibrate-treated rats than in atherosclerotic rats. Of the enzymes in the arterial wall concerned with cholesterol ester metabolism, acid cholesterol esterase activity was decreased in atherosclerotic rats, and clinofibrate treatment increased this activity. The ratio of acyl-CoA cholesterol acyltransferase activity (ACAT) to neutral cholesterol esterase activity was higher in atherosclerotic rats than in control rats and was lower in clinofibrate-treated rats than in atherosclerotic rats. From these results, it is concluded that clinofibrate modifies enzyme activities in such a way as to cause a reduction of cholesterol accumulation in the arterial wall and lowers the plasma VLDL and LDL cholesterol levels.
 ...
PMID:Effect of clinofibrate on lipid metabolism of aorta in atherosclerotic rats. 668 Sep 96

1. Dye-ligand chromatography using immobilized Cibacron blue F3GA (blue Sepharose CL-6B) and Procion red HE3B (Matrex gel red A) as matrices and general ligand chromatography employing immobilized 2',5'-ADP (2',5'-ADP-Sepharose 4B) and immobilized 3',5'-ADP (3',5'-ADP-Agarose) were employed for purification of NADPH-dependent 2-enoyl-CoA reductase and 2,4-dienoyl-CoA reductase from bovine liver (formerly called 4-enoyl-CoA reductase [Kunau, W. H. and Dommes, P. (1978) Eur. J. Biochem. 91, 533-544], as well as 2,4-dienoyl-CoA reductase from Escherichia coli. 2. The NADPH-dependent 2-enoyl-CoA reductase from bovine liver mitochondria was separated from 2,4-dienoyl-CoA reductase by dye-ligand chromatography (Matrex gel red A/KCl gradient) as well as by general ligand affinity chromatography (2',5'-ADP-Sepharose 4B/NADP gradient). The enzyme was obtained in a highly purified form. 3. The NADPH-dependent 2,4-dienoyl-CoA reductase from bovine liver mitochondria was purified to homogeneity using blue Sepharose CL-6B, Matrex gel red A, and 2',5'-ADP-Sepharose 4B chromatography. 4. The bacterial 2,4-dienoyl-CoA reductase was completely purified by ion-exchange chromatography on DEAE-cellulose followed by a single affinity chromatography step employing 2',5'-ADP-Sepharose 4B and biospecific elution from the column with a substrate, trans,trans-2,4-decadienoyl-CoA. 5. The application of dye-ligand and general ligand affinity chromatography for purification of NADPH-dependent 2,4-dienoyl-CoA reductases taking part in the beta-oxidation of unsaturated fatty acids is discussed. It is concluded that making use of coenzyme specificity for binding and substrate specificity for elution is essential for obtaining homogeneous enzyme preparations.
 ...
PMID:Purification by affinity chromatography of 2,4-dienoyl-CoA reductases from bovine liver and Escherichia coli. 674 95

To identify key enzymes that participate in acylglycerol metabolism, 12-[(5-iodo-4-azidosalicyl)amino]dodecanoyl-coenzyme A (ASACoA) was employed as a photoaffinity label for those enzymes that use fatty acyl CoA as a co-substrate. ASACoA inhibited diacylglycerol acyltransferase activity in liver microsomes and was incorporated into triacylglycerol in a microsome dependent reaction. When photoactivated, ASACoA labeled four proteins in rat liver (75, 54, 50 and 37 kDa) and in epididymal fat cell (75, 64, 54 and 37 kDa) microsomes. Photolabeling was sensitive to palmitoyl CoA. After solubilization in Triton X-114, all four proteins were concentrated into the detergent phase, indicating that they are integral membrane proteins.
 ...
PMID:Photolabeling acyl CoA binding proteins in microsome preparations. 749 96

In the male reproductive tract, very high concentrations (mmol l-1) of free L-carnitine and acetyl-L-carnitine are found in the epididymides, seminal plasma and spermatozoa. It has been reported that the uptake of free L-carnitine by spermatozoa might be related to the epididymal maturation of the sperm membrane, since a greater uptake was found by caput than by cauda spermatozoa in vitro. However, the free L-carnitine concentrations estimated inside the gametes were never greater than those of the surrounding medium. In this study, we investigated the mechanism of transport of free L-carnitine and its ester acetyl-L-carnitine, through the plasma membrane of mature and immature epididymal boar spermatozoa. In vitro, we found a passive diffusion of both compounds to the spermatozoa, whatever the maturation stage. The spermatozoa might progress in the epididymal lumen and accumulate high amounts of free L-carnitine. The active uptake of free L-carnitine occurs only across epididymal mucosa. These results are in agreement with those reported on cells of other organs that exchange pharmacological free L-carnitine concentrations (mmol l-1) by a passive mechanism through the plasma membrane. The acetylation of high amounts of free L-carnitine inside the spermatozoa was found only in caudal spermatozoa. This result suggests that oxidative metabolism (producing acetyl CoA) might be more active in mature cells. The acetyl-L-carnitine added to the incubation medium of boar spermatozoa was hydrolysed. Enzymatic activity of the sperm membrane is low and this may partially explain the low concentrations of acetyl-L-carnitine found in the caudal epididymal plasma.
 ...
PMID:Uptake and release of free L-carnitine by boar epididymal spermatozoa in vitro and subsequent acetylation rate. 818 99

To contribute to the understanding of the hypolipidemic action of etofibrate, which is the 1,2-ethandiol ester of clofibric acid and nicotinic acid, 300 mg of this drug/kg body weight or of the medium were administered daily by a stomach tube to normolipidemic rats. Some animals were decapitated at the 10th day of daily treatment (prolonged treatment), whereas others were studied at different times after one single administration (acute treatment). In animals on prolonged treatment etofibrate decreased plasma levels of cholesterol, triacylglycerols, free fatty acids (FFA) and glycerol, as well as the total and unesterified cholesterol concentrations, in liver microsomes. In these rats, etofibrate increased the activity of liver cytosolic glycerol-3-P dehydrogenase, whereas it decreased the activity of both microsomal HMG-CoA reductase and cholesterol 7 alpha-hydroxylase and did not affect acyl-CoA: cholesterol acyltransferase (ACAT). At 3, 5 and 7 h after acute treatment, etofibrate decreased plasma levels of triacylglycerols, glycerol and FFA, and this effect disappeared at 24 h, whereas plasma cholesterol did not change 3 h after etofibrate but decreased at 5 and 7 h and remained low after 24 h, and a similar change was found in the liver microsomes free cholesterol concentration. However, with the exception of a significant reduction in cytosolic glycerol-3-P dehydrogenase at 7 h and in ACAT at 5 h, acute etofibrate treatment did not affect the activity of the liver enzymes studied. At low concentrations (10(-5) M) in the incubation medium, etofibrate decreased the release of both FFA and glycerol by epididymal fat pad pieces incubated in vitro. These findings together with those previously reported by us in rats using a similar etofibrate treatment protocol [6] indicate that etofibrate decreases the availability of lipolytic products in the liver by acting on their release from adipose tissue and on their intrinsic hepatic metabolism. Consequently, this drug would decrease liver VLDL triacylglycerol synthesis and secretion, which together with facilitating the clearance of circulating triacylglycerols causes its hypotriglyceridemic effect. The hypocholesterolemic effect of etofibrate after acute treatment may be a secondary consequence of the reduced liver VLDL production caused by decreased adipose tissue lipolysis, but after prolonged treatment, this effect also seems to be influenced by the inhibition of HMG-CoA reductase activity which would reduce cholesterol synthesis.
 ...
PMID:Studies with etofibrate in the rat. Part II: A comparison of the effects of prolonged and acute administration on plasma lipids, liver enzymes and adipose tissue lipolysis. 832 74

This study was designed to examine whether short- and long-term treatments by a low level of dietary L-carnitine are capable of altering enzyme activities related to fatty acid oxidation in normal Wistar rats. Under controlled feeding, ten days of treatment changed neither body weights nor liver and gastrocnemius weights, but succeeded in reducing the weight of peri-epididymal adipose tissues. Triacylglycerol contents were lowered in liver and ketone body concentrations were found slightly more elevated in blood. In the liver, mitochondrial carnitine palmitoyltransferase I (CPT I) exhibited a slightly higher specific activity and a lower sensitivity to malonyl-CoA inhibition, while peroxisomal fatty acid oxidizing system (PFAOS) was found to be less active. Carnitine supplied for one month reduced the mass of the periepididymal fat tissue, but not those of the other studied organs, and produced a slight but non-significant gain in body weight after ten days of treatment. In the liver, CPTI characteristics were comparable in control and treated groups, while PFAOS activity was less in rats receiving carnitine. Data show that L-carnitine at a low level in the diet exerted two paradoxical effects before and after ten days of treatment. Results are discussed in regard to fatty acid oxidation in mitochondria and peroxisomes, and to the possible altered acyl-CoA/acylcarnitine ratio with increased concentrations of L-carnitine in the liver.
 ...
PMID:Effect of short- and long-term treatments by a low level of dietary L-carnitine on parameters related to fatty acid oxidation in Wistar rat. 855 64

These studies were designed to assess the effects of pioglitazone, a new oral antidiabetic agent that acts by improving insulin sensitivity, on blood pressure, plasma and tissue lipids, and insulin resistance in the Dahl salt-sensitive (Dahl-S) rat. Reaven et al had reported that male Dahl-S rats are moderately hyperinsulinemic and insulin-resistant. This was of particular interest since these rats are not obese but are hypertriglyceridemic, and on a high-salt diet they become hypertensive. In the current study, male Sprague-Dawley control and Dahl-S rats were compared when fed standard chow of high-fat, high-sucrose (HFHS) diets with or without pioglitazone (20 mg/kg body weight/d) for 3 weeks. On the standard chow diet, Dahl-S rats were hypertriglyceridemic and had high tissue levels of malonyl coenzyme A ([CoA] Dahl-S 5.0 v control 3.3 nmol/g in muscle, and Dahl-S 15.6 v control 10.7 nmol/g in liver); however, they were not hyperinsulinemic. Pioglitazone therapy decreased both malonyl CoA and plasma triglycerides toward control values, but had no effect on plasma insulin levels. On the HFHS diet, both groups became glucose-intolerant and hyperinsulinemic; however, the hyperinsulinemia was greater and more sustained in Dahl-S rats. In addition, the HFHS diet appeared to increase the mass of retroperitoneal fat in the Dahl-S but not in the control group. Treatment with pioglitazone decreased retroperitoneal fat, but as reported previously, it increased the mass of the epididymal fat pad. The results suggest that the hypertriglyceridemia of the Dahl-S rat is associated with an increase in the concentration of malonyl CoA in both liver and muscle. They also show that pioglitazone reverses both of these abnormalities independently of its effect on plasma insulin. Whether these high levels of malonyl CoA predispose the Dahl-S rat to hyperinsulinemia and possibly obesity when placed on a HFHS diet remains to be determined.
 ...
PMID:Malonyl coenzyme A and adiposity in the Dahl salt-sensitive rat: effects of pioglitazone. 860 42


<< Previous 1 2 3 4 5 6 7 Next >>