Human Plasma High-Density Lipoprotein Composition during the Menstrual Cycle

Abstract

Observations from studies during pregnancy, the menstrual cycle, and during estrogen-androgen administration have shown that gonadal steroids influence in a characteristic way the plasma lipids and particularly the high-density lipoprotein (HDL) lipids. The plasma and HDL lipid composition was followed on 5 different occasions during the menstrual cycle in 5 women. The concentrations of free cholesterol and lysolecithin varied inversely throughout the menstrual cycle. A reduction of linoleic acid in HDL lecithin occurred during the estrogen-dominated follicular phase. These changes in linoleic acid varied inversely to the changes in arachidonic acid in HDL lecithin and suggest an influence by the gonadal hormones on the lipoprotein lecithin synthesis in the liver. The present data indicate that among the fatty acids in β-position of HDL lecithin, linoleic acid is preferable to arachidonic acid for the lecithin: cholesterol acyltransferase (LCAT) reaction. A decrease of the linoleic acid content in HDL lecithin during the estrogen-dominated follicular phase would therefore give rise to an indirect influence on the LCAT reaction by reducing the most favourable substrate.

Key Words:

• Cholesteryl ester
• fatty acid composition
• high-density lipoproteins
• lecithin
• lecithin
• cholesterol acyltransferase
• menstrual cycle