Malonyl-CoA in skeletal muscle and liver of streptozotocin-diabetic rats.

Malonyl-CoA, the inhibitor of carnitine palmitoyl transferase I, has been examined in this study in the muscle and liver of diabetic rats. Male Sprague-Dawley rats were rendered diabetic with streptozotocin (6 mg/100 g body wt). The gastrocnemius/plantaris muscles and liver samples were frozen at liquid nitrogen temperature. Muscle malonyl-CoA was 1.8 +/- 0.2 pmol/mg in control rats and 1.5 +/- 0.2 pmol/mg in the diabetic rats. This difference was not statistically significant. Liver malonyl-CoA of control rats was 8.6 +/- 0.8 pmol/mg, in comparison to 4.3 +/- 0.6 pmol/mg in diabetic rats. In the liver, high concentrations of malonyl-CoA inhibit fatty acid oxidation and ketogenesis. Failure of malonyl-CoA to decline in muscle in the diabetic may be responsible in part for the diversion of fatty acids to the liver, thereby enhancing hepatic fatty acid oxidation and ketogenesis.