Lecithin:cholesterol acyl transfer in plasma of normal persons in relation to lipid and lipoprotein concentration

Information concerning variation in the lecithin:cholesterol acyl transfer (LCAT) rate in normal persons is scanty. We have therefore analyzed the LCAT rate and the lipid and lipoprotein concentrations in the plasma of healthy normolipidemic persons 20-60 years of age, 40 men and 40 women. 10 per decade and sex. Interindividual variation in molar LCAT rate was 57-130 mumol-u(-1)-h-1 (mean +/- 2 S.D.) with no sex difference. Intraindividual variation of molar LCAT rate studied in 8 women and 9 men was shown to be greater than expected from methodological error and was not explainable by the small changes in plasma lipid concentration during the observation period. In the women the molar LCAT rat was lower during the preovulatory phase of the menstrual cycle than during the postovulatory phase. There was positive correlations between the molar LCAT rate and most of the lipid parameters in plasma. By partial correlation analysis a positive correlation was shown between LCAT rate and triglyceride concentration irrespective of other lipid parameters. Keeping triglyceride concentration constant, there was a positive correlation between molar LCAT rate and total phospholipid, unesterified cholesterol, esterified cholesterol, or low-density lipoprotein (LDL) cholesterol concentration. No correlation was found between high-density lipoprotein (HDL) lipid concentration and LCAT rate. Thus in normal subjects there seems to be a direct relation between very low density lipoprotein and LDL lipid concentration and molar LCAT rate but no relation between HDL lipid concentration and LCAT rate.