Effects of chlorophenoxyisobutyrate (CPIB) on liver composition and triglyceride synthesis in rats

Abstract Chlorophenoxyisobutyrate (CPIB) or Atromid fed to rats at a level of 0.3 % of the diet has been shown to produce relatively small changes in concentration of liver total lipids, triglycerides, water, protein, and DNA, but, due to the increase in liver size of about 25 %, the increases in total liver content (per 100 g of body weight) of protein and triglyceride were found to be about 35–40 %. The rate of synthesis of liver triglyceride was shown to be increased by CPIB or Atromid, as estimated from the incorporation of tritium water, 14 C-glycerol or 14 C-acetate in vivo or from 14 C-acetate in liver slices. The increase was slight per gram of liver but considerable in terms of whole liver. The effect of CPIB in decreasing plasma triglyceride levels seems not to be due to an inhibition of hepatic triglyceride synthesis. The amount of newly synthesized (labeled) triglycerides in plasma, four hou ; after administration of the precursor, was shown to be reduced in CPIB-treated rats suggesting that the action of the drug may be an inhibition of the rate of formation of the lipoprotein in liver, or its release into plasma, or both,