Differential utilization of long chain fatty acids during triacylglycerol depletion. I. Rat heart after ischemic perfusion

Rat hearts were perfused with Krebs-Henseleit buffer for 90 min according to the Langendorff procedure. Normoxic perfusion for 90 min resulted in minor changes in fatty acid composition and a decrease in residual heart triacylglycerol to 60% of preperfusion values. When the protocol included 30 min of slow perfusion-induced ischemia, the hearts were observed to be depleted of 89% of their initial triacylglycerol content. The triacylglycerol fatty acid composition (mg %) remained similar after compared to before perfusion except for a 121 mg % increase in stearic acid and a 225 mg % increase in arachidonic acid. The percentage composition of both fatty acids was significantly inversely correlated with the amount of triacylglycerol remaining in the heart after perfusion. Postperfusion, arachidonic acid and stearic acids were present at nearly 1∶1 in the residual heart triacylglycerol, suggesting that a common mechanism may be involved in the selective retention of these fatty acids by the heart. This paper was presented in part at the annual meeting of the Canadian Federation of Biological Societies, Guelph, Ontario, June 16–22, 1986. S.C.C. was the recipient of an Industrial Research Fellowship from the National Science and Engineering Research Council of Canada (1982–1986).