Acute effects of cholestyramine on serum lipoprotein concentrations in type II hyperlipoproteinaemia.

Twelve subjects with primary type IIA hyperlipoproteinaemia were treated with cholestyramine under metabolic ward conditions in order to study the timing of effects of different serum lipoprotein classes. After 1 day's treatment changes occurred in all 3 classes, i.e., very low (VLDL), low (LDL) and high (HDL) density lipoprotein classes. VLDL increased abruptly and remained constant during treatment. The ratio of cholesterol/triglycerides decreased suggesting the formation of larger particles. LDL cholesterol decreased continuously suggesting a different mechanism behind this effect than that on VLDL. LDL triglyceride remained constant indicating a relative increase of LDL1. HDL cholesterol decreased while HDL triglycerides increased. All changes made the lipoprotein pattern more "type IV-like". The findings were in agreement with an increased formation of VLDL and an increased flux of lipoprotein through the cascade VLDL-IDL-LDL1-LDL2.