Effect of diabetes and starvation on myocardial triglyceride and free fatty acid utilization

Abstract

The hydrolysis, uptake, and oxidation of chylomicron tripalmitin- C14 by the perfused rat heart was related to the triglyceride concentration in the perfusate. The hydrolysis, uptake, and oxidation of chylomicron tripalmitin-C14 by hearts of alloxan-diabetic rats were less than those of control animals. Hearts of fasted normal rats demonstrated changes that were qualitatively similar to those produced by alloxan diabetes. Palmitate-I-C14 uptake and oxidation by hearts of alloxan-diabetic rats were decreased and were associated with a twofold increase in glycerol release. There was a 50% decrease in the specific activity of palmitate-I-C14 in the perfusate from hearts of alloxan-diabetic rats, as contrasted with a 16% decrease for hearts of control animals. Therefore, net uptake of free fatty acids by hearts of diabetic rats was decreased. The findings are compatible with increased turnover and utilization of endogenous lipid by hearts of alloxan-diabetic rats and increased exchange of myocardial fatty acids for those in the perfusate.