INTERMEDIATE DENSITY LIPOPROTEINS AND HEPATIC LIPASE IN POSTMENOPAUSAL WOMEN

In order to evaluate atherogenic lipoproteins in post-menopause, we studied 73 healthy women, 49 to 65 years old (Post-menopausal Group), with 1 to 10 years of amenorrhea and body mass index below 27 Kg/m2, and 20 young women (Control Group). We have determined plasma cholesterol concentration in the lipoproteins of intermediate density in addition to the classical lipoprotein parameters: total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and fractionation of lipoproteins by electrophoresis. In 63 women from the Post-menopausal Group and 16 from the Control Group we studied the activity of hepatic lipase. Among these patients we selected at random 25 post-menopausal women and 13 controls to add measurements of triglycerides in the lipoproteins of intermediate density. Table 1 shows that the average plasma concentration of total cholesterol in the Post-menopausal Group was higher than that of the Controls (p < 0.001). The same was found for LDL-cholesterol (p < 0.001) and for triglycerides (p < 0.001) whereas the average concentration of HDL-cholesterol did not show significant differences. The Post-menopausal Group had high values of plasma lipoproteins of intermediate density, even with normal phenotypes (Table 2). Cholesterol but also triglycerides (Fig. 1) were responsible for this increase. A triglyceride rich lipoprotein subspecies of intermediate density was predominant in 73% of Post-menopausal women vs 23% of the Controls (p < 0.01, Table 3). No differences in hepatic lipase activity were seen between the two groups (Table 4), and non statistic correlation between the enzyme activity and IDL-triglycerides or HDL-cholesterol. This work shows an atherogenic profile in the Post-menopausal Group due to an increase in plasma concentration of LDL-cholesterol and triglyceride-rich intermediate density lipoproteins.