The absorption and metabolism of short and long chain fatty acids in puromycin-treated rats

Abstract

The metabolism of short and long chain fatty acids and triglycerides was compared in control and puromycin-treated rats. The drug had no effect on the absorption of octanoic acid and of trioctanoin, presumably because short chain fatty acids are absorbed directly into the portal stream as albumin-bound free fatty acid. However, long chain fatty acid absorption into the thoracic duct lymph in the form of chylomicron triglycerides was inhibited by puromycin. Nonetheless, oxidation of the administered long chain fatty acid contained in the test meal to CO 2 was equal in puromycin-treated rats and in control animals. In thoracic-duct-cannulated animals treated with puromycin, the amount of expired label CO 2 derived from a test meal of long chain lipids varied inversely to the amount of label in the lymph lipid. Long chain fatty acids therefore can be absorbed directly into the portal venous system. In the human genetic disorder, abetalipoproteinemia, the route of absorption of long chain fatty acids is probably via the portal venous system.