HDL biology
CETP activity rises in the second trimester of pregnancy alongside falling hepatic lipase and rising estradiol (J Lipid Res 1996)
Original title: Longitudinal study on lipoprotein profile, high density lipoprotein subclass, and postheparin lipases during gestation in women
Twenty-five healthy pregnant women were followed longitudinally through three trimesters, post-partum, and (for 11 of them) post-lactation, to understand the mechanism of maternal hyperlipidemia. Triglyceride and cholesterol rose with gestation across all lipoprotein fractions, with the largest changes in LDL and HDL triglyceride/cholesterol ratios; HDL2b proportion increased with gestation while HDL3a and HDL3b decreased most. CETP activity increased during the second trimester, postheparin lipoprotein lipase activity fell during the third trimester, and postheparin hepatic lipase activity declined progressively from the first trimester as 17 beta-estradiol, progesterone, and prolactin all rose. Lipoprotein triglyceride values correlated negatively with the logarithm of postheparin lipase activities, with hepatic lipase showing the strongest correlation with HDL-triglycerides (r = -0.757) and with estradiol (r = -0.783). The authors conclude that estrogen-driven increases in VLDL production and decreases in hepatic lipase activity play a key role in gestational lipoprotein triglyceride accumulation.
Original abstract
To understand the mechanism responsible for maternal hyperlipidemia, 25 healthy pregnant women were studied longitudinally during the three trimesters of gestation and at post-partum, and 11 were studied again at post-lactation. Triglyceride and cholesterol levels increased with gestation in all the lipoprotein fractions. However, the greatest change appeared in low density (LDL) and high density (HDL) lipoproteins, both of which showed an increase in their triglyceride/cholesterol ratio. The proportional distribution of HDL subfractions showed that the HDL2b fraction was the only one that increased with gestation, whereas both HDL3a and HDL3b had the greatest decrease. Cholesteryl ester transfer protein activity increased during the second trimester of gestation. While postheparin lipoprotein lipase activity decreased during the third trimester, postheparin hepatic lipase activity progressively decreased from the first trimester. The 17 beta-estradiol, progesterone, and prolactin hormones progressively increased from the first trimester of gestation. The lipoprotein-triglyceride values correlated linearly and negatively with the logarithm of either postheparin lipase activities, HDL-triglycerides showing the highest correlation coefficient when plotted against the hepatic lipase values (r = -0.757). It appeared that the highest correlation between any of the HDL subclasses and the activity of the enzymes was for hepatic lipase activity versus HDL2b (r = 0.456) or HDL3a (r = 0.519). A significant lineal correlation also appeared between the postheparin hepatic lipase activity and the logarithm of any of the sex hormones studied, the highest value corresponding to estradiol (r = -0.783). Therefore, during gestation, the effect of estrogen in enhancing very low density lipoprotein (VLDL) production and decreasing hepatic lipase activity plays a key role in the accumulation of triglycerides in lipoproteins of density higher than VLDL.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.