Rapid induction of essential fatty acid deficiency by intragastric infusion of triolein-supplemented total parenteral nutrition solutions: evidence of increased hepatic cholesterol esterification in the rat.

Rats were fed linoleic acid from a safflower oil emulsion or triolein-supplemented total parenteral nutrition solutions by continuous intragastric infusion for 7 and 14 d. Biochemical signs of essential fatty acid deficiency (EFAD) developed in rats supplemented with triolein compared with those receiving linoleic acid, and the relationship between hepatic cholesterol esterification and the distribution of free cholesterol in plasma lipoproteins was investigated in the EFAD and control animals. Results indicate that hepatic triglyceride (TG) and cholesterol ester content are greater and plasma levels of TG and cholesterol are lower in triolein-supplemented groups. Hepatic accumulation of cholesterol esters is associated with an increase in hepatic acyl-CoA:cholesterol acyltransferase activity and also with plasma very low density lipoprotein (VLDL) and high-density lipoprotein (HDL), which contain a greater proportion of cholesterol esters. These data suggest that EFAD can be rapidly induced with continuous intragastric feeding and that hepatic accumulation of cholesterol esters and enrichment of VLDL and HDL with cholesterol esters are early indicators of EFAD in the rat.