Uptake of fatty acids by isolated heart myocytes

An adult rat heart myocyte preparation was used to study the uptake and metabolism of the 1-14C-labelled fatty acids decanoate, laurate, myristate, and palmitate. Metabolism was saturable, but free fatty acid accumulation was not. Use of metabolic inhibitors indicated that metabolism and not uptake was rate limiting at 37 degrees C and that uptake was energy dependent. Competition was demonstrated for the metabolic pathways but not for free fatty acid accumulation. The activation energy for uptake decreased with increasing fatty acid chain length. A diffusion mechanism for long chain fatty acid uptake is proposed.