Initial cholesterol esterif ication rate in hyperlipoproteinaemia: effects of triglyceride-rich Iipoproteins

. The initial cholesterol esterification rate (LCAT activity) was determined in ninety-four hyper-lipidaemic subjects. LCAT activity was elevated in hypertriglyceridaemia, whereas patients with hyper-cholesterolaemia had normal activities. In hypertri-glyceridaemic subjects LCAT activity correlated with the concentrations of d 1.006 lipoproteins, plasma triglycerides, cholesterol and cholesterol esters and phospholipid levels. Addition of d 1.006 fraction dropped, but still was higher than in normal plasma and correlated with the amount of d 1.006 lipoproteins originally present. Thus, high LCAT activity in hypertriglyceridaemia cannot be explained solely by the presence of an increased d < 1.006 lipoprotein concentration. An increase of enzyme concentration or changes in concentration or composition of other lipoproteins (high density lipoproteins) may contribute to the high LCAT activity in hypertriglyceridaemia.