Normal and thyroidectomized male rats were fed powdered Rockland Mouse/Rat Diet (complete) with and without 0.3% clofibrate, ab lib. , for 7 days. At the end of the feeding period the rats were killed by decapitation, livers were removed, and liver mitochondria were isolated and studied. In normal rats, clofibrate increased liver weight, mitochondrial yield per g of liver, and mitochondrial oxidations, in state 3, of α-glycerophosphate, octanoate, palmitate, octanoylcarnitine and palmitoylcarnitine; however, the oxidation of succinate in states 3 and 4 was not altered. Thyroidectomy resulted in decreased liver weight and decreased mitochondrial oxidation of α-glycerophosphate, succinate, octanoate, and palmitate. Administration of clofibrate to thyroidectomized rats increased mitochondrial oxidations of octanoate and palmitate but did not affect liver weight or oxidations of succinate and α-glycerophosphate.
