Fatty acid and lactate metabolism by heart homogenates from alloxan-diabetic dogs.

Myocardial homogenates from control of alloxan-diabetic dogs were incubated in the presence of lactate or palmitate as the sole substrate. The rate of lactate oxidation of the homogenates from diabetic dogs was less than half of the oxidation rate of homogenates from control animals. The incorporation of labelled palmitate into triglyceride was greatly enhanced in the heart taken from diabetic animals. The tissue concentration of l-carnitine was twice and that of triglyceride was three times as high in the diabetic animals as in their control counterparts. Thus the myocardium of diabetic animals exhibited both altered substrate utilization and increased rate of triglyceride synthesis.