Relative increase in apolipoprotein CII content of VLDL and chylomicrons in a case with massive type V hyperlipoproteinaemia by nicotinic acid treatment.

VLDL of fasting serum was fractionated into 4 fractions of decreasing particle size by preparative ultracentrifugation in a density gradient from a patient with massive type V hyperlipoproteinaemia before and after treatment with 12 g daily of nicotinic acid. Serum triglycerides fell from 58 to 9 mmol/1 in response to treatment due particularly to reduction of larger VLDL particles. Total, insoluble (apoprotein B) and soluble protein of all VLDL fractions also fell but the ratio of these 3 protein fractions to triglyceride rose particularly in the smaller VLDL fractions. The relative amount of apolipoprotein CII increased in all fractions and the ratio apo CII to triglycerides increased by 60--90% in all VLDL fractions. The relative amounts of apo CI, apo CII-2 and apo E appeared also to increase. The results are consistent with the hypothesis that low amounts of apo CII may play a role for the development of hypertriglyceridaemia.