Regulation of palmitoylcarnitine oxidation in isolated rat liver mitochondria. Role of the redox state of NAD(H).
The redox-mediated regulation of palmitoylcarnitine oxidation was studied in isolated rat liver mitochondria in which the mitochondrial free NADH/NAD+ ratio was controlled by graded concentrations of acetoacetate and ketomalonate in a rotenone and malonate-inhibited system in the presence of ADP. The NADH/NAD+ ratio was buffered kinetically by adjusting the concentrations of the hydrogen acceptor substances and determined by calibrated NAD(P)H fluorometry of the mitochondrial suspension. A two-fold variation in the beta-oxidation rate and a five-fold variation in the free NADH/NAD+ ratio was obtained in the presence of rotenone. A non-linear negative correlation was found between the acetyl-CoA concentration and the beta-oxidation rate and a negative correlation between the long-chain acyl-CoA concentration and the beta-oxidation rate. The data indicate that the redox state is a partial controller of the beta-oxidation rate in liver mitochondria. The contribution of acetyl-CoA, a putative regulator of beta-oxidation at the acyl-CoA thiolase step is small under the conditions used.
D000090:Acetoacetates / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives*; D003574:Cytochrome c Group / Q000378:metabolism; D005470:Fluorometry; D008297:Male; D008314:Malonates / Q000378:metabolism / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000378:metabolism*; D008954:Models, Biological; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010172:Palmitoylcarnitine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012402:Rotenone / Q000378:metabolism
D000090:Acetoacetates; D000214:Acyl Coenzyme A; D003574:Cytochrome c Group; D008314:Malonates; D012402:Rotenone; D009243:NAD; D010172:Palmitoylcarnitine; C016635:acetoacetic acid; D009249:NADP; D000244:Adenosine Diphosphate; C008375:mesoxalic acid; D000105:Acetyl Coenzyme A; C030290:malonic acid; D002331:Carnitine