Metabolism of palmitic acid in perfused rat heart

Abstract

Metabolism of fatty acid was studied in the isolated rat heart perfused with albumin-bound palmitate-C 14 . Uptake of fatty acid by the heart was related to the concentration of fatty acid present and the molar ratio of fatty acid to albumin in the perfusion fluid. Disappearance of lipid-bound radioactivity from the perfusion fluid (palmitate-C 14 uptake) was consistently greater than disappearance of titratable fatty acid. This was attributed to failure of equilibration of unlabeled "endogenous" fatty acid on albumin with added palmitate-C 14 and possibly to release of unlabeled fatty acid from the heart to the perfusion fluid. The principal fates of palmitate-C 14 were C 14 O 2 and saponifiable tissue lipid. The maximal rate of recovery of palmitate-C 14 as C 14 O 2 was equivalent to 83% of total CO 2 production of the isolated perfused heart in 30 min.