Synthesis of plasma triglycerides in endogenous hypertriglyceridemia.

Radioisotopic kinetic studies of triglyceride fatty acid synthesis from serum free fatty acids have been performed in 20 studies of normal and lipemic subjects. The lipemic subjects were characterized as having carbohydrate-responsive endogenous lipemia, and were classified as having either Type III or Type IV prebetalipoproteinemia. In the untreated state, triglyceride production was reduced relative to concentration of triglyceride when compared with the normal control population. In response to carbohydrate restriction an absolute reduction in triglyceride synthesis from free fatty acids was demonstrated. These data indicate that overproduction cannot be importantly implicated as the etiology of this form of endogenous lipemia. The patients thus represent a pathophysiological entity which is distinct from the normal physiological lipemia induced by carbohydrate feeding in which overproduction is reported to be the initiating event.