The effects of diabetes on myocardial fatty acid metabolism will be studied in isolated rat hearts. Major emphasis will be placed on determining the changes in tissue levels of CoA and carnitine during the development of diabetes following injection of alloxan. Rates of CoA synthesis will be studied in vitro by determining the uptake and incorporation of 14C-pantothenic acid into CoA. The mechanism of changes in tissue carnitine will be studied by determining the rates of 14C-L-carnitine uptake by isolated hearts and tissue and serum levels of carnitine in normal and diabetic animals.