Fatty acid-binding capacity of cytosolic proteins of various rat tissues: effect of postnatal development, starvation, sex, clofibrate feeding and light cycle

Abstract

Fatty acid-binding capacity of dealbuminized, delipidated cytosolic proteins from rat tissues was studied with a radiochemical binding assay. Oleate-binding capacity ranges from 1.6 to 4.4 pmol/μg cytosolic protein in liver, heart, kidney, adrenal, brain, skeletal muscle and diaphragm. Differences in binding affinity indicate the presence of different fatty acid-binding proteins in these tissues. No change in fatty acid-binding protein content of heart and liver cytosol was observed during postnatal development up to 70 days. Starvation did not affect the fatty acid-binding capacity of heart cytosol, but increased the oleate-binding capacity in liver cytosol. Sex-related differences of binding by heart and liver cytosolic proteins were found with oleate, but not with palmitate. Fatty acid-binding capacity of liver and heart cytosol did not show marked diurnal variation. Clofibrate treatment had different effects on the oleate-binding capacity of cytosolic proteins: an increase in liver and kidney, no change in skeletal muscle and a decrease in heart. The results are discussed in relation to data concerning fatty acid oxidation.