Lecithin: cholesterol acyl transfer rate in plasma and its relation to lipid and lipoprotein concentrations in primary hyperlipidemia.

Plasma lecithin: cholesterol acyl transfer (LCAT) rate and concentrations of lipids in plasma and lipoproteins were studied in 107 hyperlipidemic subjects. In all types of hyperlipoproteinemia LCAT rates were higher than in a normolipidemic reference group. LCAT rates were highest in type IV and V. There was a considerable overlap of LCAT rates between type IIa, IIb and reference subjects. The LCAT rate correlated positively with very low density lipoprotein concentration, body mass and excess body mass. Low density lipoprotein concentration correlated positively with the LCAT rate only in the reference group. The high density lipoprotein concentration correlated negatively with the LCAT rate. It was suggested that the LCAT rate in vitro reflects the in vivo turnover of cholesteryl esters as a part of the turnover of apoprotein-B containing lipoprotein complexes in plasma. The results might then indicate an inflow rate of lipoproteins in plasma that is increased in most type IV cases but normal or only moderately increased in type IIa and IIb subjects. Analysing the relations between the LCAT rate and the concentrations of lipids in plasma by multiple regression indicated hypothetically deficiencies of lipoprotein removal from plasma in half of type IIa and one third of type IIb subjects.