Long and medium chain triglycerides increase plasma concentrations of ketone bodies in suckling rats

The potential of medium chain triglyceride (MCT) and long chain triglyceride (LCT) as sources of plasma ketones was investigated in suckling rats. Initially high concentrations of plasma ketones in 6-, 10, and 17-day-old rats increased 2- to 3-fold after acute feeding of MCT. This feeding had the same effect in fed or fasted adult rats. Corn oil (as a source of LCT) induced a large increase in the plasma ketone concentration of suckling rats and a relatively small but significant increase in fasted adult rats. The LCT treatment did not affect plasma ketone levels in fed adult rats. The results show clearly that feeding either LCT or MCT will enhance hyperketonemia in suckling rats. In the livers of all animals, regardless of age, the capacity for incorporation of [1(-14C)]octanoate into CO2 and acetoacetate far exceeded that for [1(-14C)]palmitate. The hyperketonemic action of LCT in suckling rats was accompanied by an increased activity of carnitine palmityltransferase and increased level of carnitine.