TRANSPORT OF FREE FATTY-ACID AND TRIGLYCERIDE IN ANHEPATIC RATS

Without a liver the fractional plasma removal of free fatty acid is one third and chylomicron triglyceride one half of that in the intact rat. The intestine of the anhepatic rat converted enteral fatty acid to plasma triglyceride but was unable to do the same for plasma free fatty acid. This decrease in plasma free fatty acid removal and the inability to recycle the acid as triglyceride were, in part, responsible for the conversion of large fractions of plasma triglyceride flux to the plasma free acid in hepatectomized rats. Increased intravascular triglyceride lipolysis resulting from high circulating lipoprotein lipase concentrations and reduced plasma triglyceride removal were other factors shifting the partition of anhepatic plasma fatty-acid transport from the ester to the free. After the anhepatic plasma clearance of either free fatty acid or triglyceride, relatively more of both compounds was recovered in the lipid of actively metabolizing (heart and muscle) as opposed to storage (adipose) tissue when compared with controls. Sequential evaluations of the recovery of plasma free fatty acid and triglyceride in tissues of anhepatic rats demonstrated accumulation or storage solely in adipose tissue and only when the plasma fatty acid was in triglyceride. This observation and the large conversion of anhepatic circulating triglyceride to the free acid may, in part, explain the lack of an increase in adipose lipid with reduced hepatic mass. The data help explain the preferential use of a lipid fuel in liver disease and the difficulties in obtaining carbon storage in this condition.