Serum lipoproteins in rats with carbon tetrachloride-induced fatty liver

After the administration of CCl4 to male rats, liver triglycerides began to increase after a lag period of about 1 hr; the level of serum triglycerides fell sharply during the first 30 min of intoxication.Three classes of serum lipoproteins were isolated by flotation in the ultracentrifuge and their concentrations and chemical compositions were determined. Within 4 hr of the administration of CCl4 the level of the very low density (VLD-) lipoproteins fell to 25% of that in the control rats. Smaller decreases in the levels of the other two classes of lipoproteins were evident. The serum concentration of all the components of the VLD-lipoproteins were reduced, but proportionally more lipids were bound to the protein moiety in the CCl4-treated rats than in the controls. The concentrations of protein and triglycerides of the VLD-lipoproteins declined most steeply during the first hour of intoxication.The results are interpreted as further evidence that the fatty liver induced by CCl4, is due to a block in the release of hepatic triglycerides to the plasma, the primary lesion being, very probably, inhibition of the synthesis of the protein moiety of serum lipoproteins.