Studies in cholestasis of pregnancy. VI. Fatty acid composition of glycero-phospholipids before and after delivery.

Abstract

Eight pregnant women, complaining of generalized pruritus with lipoprotein-X (LP-X) in their serum and diagnosed as cases of cholestasis of pregnancy (CP)--were studied during pregnancy and after delivery. Ten women with uncomplicated normal pregnancy served as controls. LP-X, liver function tests and relative fatty acid composition of serum lecithin (determined by gas-liquid chromatography, GLC) were followed. The fatty acid composition in liver and serum lecithin is determined by the synthesis pathways of lecithin in the liver. The faster and quantitatively dominating cytidine-diphosphate diglyceride pathway, pathway I, causes the appearance of lecithin with palmitic acid (16:0) in 1-position and oleic (18:1) or linoleic (18:2) acid in 2-position, while pathway II, with methylation of phosphatidyl-ethanolamine (cephalin) preferentially cases the appearance of lecithin with stearic acid (18:0) in 1-position and arachidonic acid (20:4) in 2-position. Pathway I is enchanced by oestrogenic and pathway II by cholestatic influence. During pregnancy women with CP were characterized in their serum lecithin fatty acid composition by a high palmitic (16:0) and a high oleic (18:1) acid content, in agreement with earlier studies. After delivery, in women with prior CP a decrease in palmitic (16:0) and linoleic (18:2) acids and an increase in stearic (18:0) acid, was interpreted as decreased influence on the major lecithin synthesis pathway I and an enhancement of pathway II. In addition, after delivery in the lactating mother, serum lecithin fatty acid composition data revealed an essential fatty acid (EFA) "consumption." It was earlier shown, that women with previous CP (when studied 8--21 months after delivery) had as judged from their serum lecithin fatty acid composition, a "basic metabolic defect," expressing presumably as estrogen enhanced pathway II of liver lecithin synthesis. In the present study, soon after delivery (on day 4--8) women with prior CP showed, however, less pathway II influence than women with a prior normal pregnancy. This was interpreted as a presistence of the cholestatic influence on liver lecithin synthesis pathways at this short time after delivery. Serum lecithin fatty acid composition appears to be a sensitive variable for the evaluation of metabolic influences in the liver.