Liver Lipid Accumulation in Isoleucine-deficient Rats

Abstract

Rats made acutely deficient in isoleucine by force-feeding a diet completely devoid of isoleucine, had higher concentrations of liver triglycerides than control rats. When liver slices from fed, but deficient rats were incubated with acetate-2-C14, total incorporation of the label into the fatty acids of triglycerides was nearly 4 times higher than in the triglycerides of control livers. Fatty acid analyses of the triglycerides of deficient rat livers revealed higher proportions of palmitic, stearic and oleic acids and lower proportions of linoleic and arachidonic acids than were in control livers. Lipoprotein synthesis appeared not to be impaired by the deficiency, since there were no differences in serum cholesterol, phospholipid, and lipoprotein concentrations in the 2 groups. Some impairment in the removal of liver triglyceride in deficient rats was suggested, however, because more linoleic acid accumulated in these animals than in the controls. The results indicated, therefore, that increased fatty acid synthesis in the liver may have been an important factor contributing to the excessive accumulation of liver triglyceride in isoleucine-deficient rats.