Influence of dietary fatty acids on membrane properties and enzyme activities of liver mitochondria of normal and hypophysectomized rats

Studies are reported on the effects of diets containing fatty supplements with (A) a high concentration of arachidonate (46% concentrate of ethyl arachidonate), (B) a high concentration of linoleate (corn oil), and (C) an essential fatty acid deficient, fully saturated fat (hydrogenated coconut oil) upon lipid composition, membrane permeability, and enzyme activities of liver mitochondria of normal and hypophysectomized rats. The fatty supplements produced differences in the fatty acid composition of the liver mitochondria; hypophysectomy, in addition, influenced the neutral and phospholipid composition. Permeability, indicated by swelling properties, correlated generally with the degree of unsaturation and essential fatty acid content of the lipid of the mitochondria of the normal animals. The fatty supplements also influenced the enzyme acitivites of the mitochondria of the normal animals. The mitochondria of the hypophysectomized animals were less responsive to the differences in the dietary fat in both their swelling properties and enzyme activities. Although the relationship was complex, it appeared that the hypophysis was involved in the functions of essential fatty acids in liver mitochondria.