Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxfenicine inhibits myocardial metabolism of nonesterified fatty acids (NEFA). The purpose of the present study was to examine the effects of oxfenicine on triglyceride accumulation and the development of histologically visible lipid droplets. The beta-agonist isoproterenol was used to induce elevated arterial NEFA. Four groups of rats were used in the experiment (12 to 14 rats in each group), and each group received two subcutaneous injections, the second injection 25 min after the first, of oxfenicine-isoproterenol, oxfenicine-saline, saline-isoproterenol and saline twice, respectively. One hour after the second injection, the rats were anesthetized, and the hearts from six rats from each group were quickly removed and frozen for later analysis of triglyceride content. From the remaining rats blood samples were drawn for NEFA analysis, and biopsies were taken from the left ventricular wall before the hearts were frozen in liquid nitrogen and prepared for analysis of esters of carnitine and CoA. Quantitative morphometric techniques were used to determine the fractional volume of lipid droplets in myocardial biopsies. Our results show a marked increase in the triglyceride and lipid droplet content in all groups receiving oxfenicine or isoproterenol. The effect was most pronounced after treatment with both drugs. The close association between the increase in triglyceride and lipid droplet supports the notion that the lipid droplets are composed of triglycerides. Our finding that oxfenicine induces lipid droplet accumulation independent of NEFA increase supports the hypothesis that oxfenicine exerts its effect by inhibiting carnitine acyl transferase.
J Mol Cell Cardiol 1988 Mar
PMID:Oxfenicine-induced accumulation of lipid in the rat myocardium. 339 58

Two fatty acid blocking agents, oxfenicine (33 mg/kg) and 4-bromocrotonic acid (0.34 mg/kg/min for 70 min), were used to selectively adjust levels of long-chain acyl CoA and carnitine in aerobic and ischemic myocardium. The purpose of the study was to test whether the shift in these amphiphiles was associated with alterations of mechanical function in intact myocardium. The extracorporeally perfused swine heart preparation was used. Hearts were perfused at aerobic levels for 40 min following which flow to the anterior descending (LAD) circulation was reduced by 50% for the final 30 min of perfusion. All hearts were perfused with excess fatty acids to raise serum levels to 1.37 +/- 0.16 mumol/mol throughout the studies. Oxfenicine and 4-bromocrotonic acid affected a 20% (P less than 0.05 and P less than 0.05, respectively) further decline in 14CO2 production from labelled palmitate as compared with placebo hearts during regional ischemia. Accompanying this were downward shifts in acyl carnitine (-27 delta %, NS in aerobic tissue; -70 delta %, P less than 0.001 in ischemic tissue) and acyl CoA (-13 delta %, NS in aerobic tissue; -33 delta %, P less than 0.01 in ischemic tissue) for oxfenicine and upward shifts of acyl carnitine (+212 delta %, P less than 0.001 in aerobic tissue; -9 delta %, NS in ischemic tissue) and acyl CoA (+78 delta %, P less than 0.001 in aerobic tissue; +29 delta %, P less than 0.025 in ischemic tissue) for 4-bromocrotonic acid. These adjustments in amphiphiles were further associated with improved function (+55 delta % increase in max LV dP/dt, P less than 0.05) in oxfenicine-treated hearts and depressed function (+87 delta % increase in LVEDP, P less than 0.05) in 4-bromocrotonic acid-treated hearts. Thus, at comparable conditions of coronary flow, left ventricular pressure, and fatty acid availability and oxidation between treatments, depletion or build-up of CoA and carnitine esters as affected by selective inhibitors of fatty acid metabolism were causally linked to improved or impaired cardiac performance in intact hearts.
J Mol Cell Cardiol 1987 May
PMID:Effects of the fatty acid blocking agents, oxfenicine and 4-bromocrotonic acid, on performance in aerobic and ischemic myocardium. 362 84

High concentrations of lactate and oxfenicine inhibit fatty acid oxidation in cardiac muscle. The site of this inhibition was investigated in isolated perfused rat hearts. In hearts perfused with glucose (11 mM) and [U-14 C]palmitate (1.0 mM), addition of 5 mM lactate caused a 38% reduction in 14CO2 production. Tissue levels of long-chain acyl carnitine decreased suggesting that inhibition occurred at either fatty acyl CoA synthetase or carnitine-acyl CoA transferase. Cytosolic levels of acyl-CoA are low compared with mitochondrial levels and changes in acyl-CoA within the cytosolic compartment cannot be estimated directly. Consequently, the rate of conversion of 14C-palmitate to neutral lipids was used as an indicator of cytosolic acyl CoA levels. Lactate caused a 100% increase in 14C-fatty acid conversion to triglycerides suggesting that cytosolic levels of acyl-CoA increased in association with decreased acyl-carnitine. This indicates that lactate inhibited FFA oxidation at the level of carnitine-acyl CoA transferase. Oxfenicine (2 mM) reduced fatty acid oxidation by 45%, decreased acyl-carnitine levels by 80%, and increased conversion of 14C-palmitate to neutral lipids by 44%, suggesting that oxfenicine also inhibits fatty acid oxidation at the level of carnitine-acyl CoA transferase. These data further indicate that carnitine-acyl CoA transferase is an important site of control in the pathway of fatty acid oxidation.
J Mol Cell Cardiol 1985 Jun
PMID:Inhibition of carnitine palmitoyl-CoA transferase activity and fatty acid oxidation by lactate and oxfenicine in cardiac muscle. 392 8