Plasma-triglycerides do not regulate high-density lipoprotein concentrations.

Diets high in carbohydrate and diets restricted in fat and calories were used to induce large fluctuations in plasma-triglycerides in patients with severe familial hypertriglyceridaemia. High-density-lipoprotein (HDL) concentrations were estimated by radioimmunoassay of the major HDL apoprotein, apo A-I, and were correlated with plasma cholesterol and triglyceride concentrations. Patients with type-1 hyperlipoproteinaemia had apo A-I concentrations about 50% of normal, and no increase in apo A-1 concentrations was observed even when plasmatriglycerides were reduced to the normal range. Apo A-I concentrations in type-5 hyperlipoproteinaemia were not consistently low and did not correlate with plasma-lipid concentrations. It does not seem that hypertriglyceridaemia reduces HDL in either disorder.