Salient effects of L-carnitine on adenine-nucleotide loss and coenzyme A acylation in the diabetic heart perfused with excess palmitic acid. A phosphorus-31 NMR and chemical extract study.
The beneficial effects of L-carnitine perfusion on energy metabolism and coenzyme A acylation were studied in isolated hearts from control and diabetic rats. All hearts were perfused at a constant flow rate with a glucose/albumin buffer which contained 2.0 mM palmitate. 31P-NMR was utilized to assess sequential phosphocreatine and ATP metabolism during 1 h of recirculation perfusion. L-Carnitine (5.0 mM final concentration) was added after 12 min of baseline recirculation perfusion. Frozen samples were taken after 1 h of recirculation perfusion for spectrophotometric analysis of high-energy phosphates and the free and acylated fractions of coenzyme A. L-Carnitine perfusion of diabetic hearts attenuated or prevented the reduction of ATP observed in untreated diabetic hearts. It also attenuated the accumulation of long-chain fatty-acyl coenzyme A. Although L-carnitine improved myocardial function in diabetic hearts, this was independent of any direct effect on physiological indices. Thus, the salutory effect of acute perfusion with L-carnitine on energy metabolism in the isolated perfused diabetic rat heart appears to be a direct effect on lipid metabolism.
D000214:Acyl Coenzyme A / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002331:Carnitine / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects; D006439:Hemodynamics; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D000214:Acyl Coenzyme A; D000227:Adenine Nucleotides; D010169:Palmitic Acids; D019308:Palmitic Acid; D000255:Adenosine Triphosphate; D002331:Carnitine