Inhibition of palmitoylcarnitine oxidation by pyruvate in rat heart mitochondria.
The oxidation of 1-14C-palmitoylcarnitine by rat heart mitochondria has been measured by assessing both the disappearance of substrate and the appearance of labelled products. Pyruvate inhibited palmitoylcarnitine oxidation by about 40%. Fifty percent inhibition occurred at about 20 mumol/L pyruvate. The inhibitory effect of pyruvate required entry of pyruvate into mitochondria since it did not occur in the presence of alpha-cyano-4-hydroxycinnamic acid, an inhibitor of the mitochondrial pyruvate transporter. The inhibitory effect of pyruvate also required an active pyruvate dehydrogenase. These studies indicate a mechanism that may be important in the replacement of fatty acids by carbohydrate as fuels of respiration of the heart during the transition from the starved to the fed state.
D000818:Animals; D001692:Biological Transport; D002331:Carnitine / Q000031:analogs & derivatives*; D003373:Coumaric Acids / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D003999:Dichloroacetic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008929:Mitochondria, Heart / Q000378:metabolism*; D010084:Oxidation-Reduction; D010172:Palmitoylcarnitine / Q000378:metabolism*; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D014475:Uncoupling Agents / Q000494:pharmacology
D003373:Coumaric Acids; D011768:Pyruvate Dehydrogenase Complex; D011773:Pyruvates; D014475:Uncoupling Agents; D010172:Palmitoylcarnitine; C007175:alpha-cyano-4-hydroxycinnamate; D003999:Dichloroacetic Acid; D002331:Carnitine