Relative Fatty Acid Composition of Lecithin during Postmenopausal Replacement Therapy – A Comparison between Ethinyl Estradiol and Estradiol Valerate

Abstract

The relative fatty acid composition of serum lecithin was followed in groups of women during postmenopausal replacement therapy. The effects of estradiol valerate and ethinyl estradiol in two different doses, and the modulating influence of various progestogens and antiestrogens were compared. Unopposed estrogen treatment enhanced liver lecithin synthesis along pathway I, i.e. reduced the amount of stearic acid and increased the amount of palmitic acid. The effect was clearly dose-dependent and even the low dose of 10 µg of ethinyl estradiol was more potent than 2 mg of estradiol valerate. No qualitative difference between the two estrogens was recorded. The sequential addition of the antiestrogen tamoxifen significantly reduced the influence of ethinyl estradiol. Liver lecithin synthesis along pathway I may be stimulated by all estrogens and not only by 17C-alkylated compounds. The prostaglandin precursors, dihomogammalinolenic and arachidonic acid, showed a seemingly dose-dependent increase during estrogen treatment. The comparatively weaker effects of estradiol valerate on lipid metabolism should make this non-alkylated estrogen the first choice in clinical practice.

Conversion of α-linolenic acid to longer-chain polyunsaturated fatty acids in human adults

“…The suggestion that oestrogen may increase the activity of the desaturation/elongation pathway is consistent with the finding that oestrogenbased hormone replacement therapy in postmenopausal resulted in greater plasma dihomo-γ-linolenic and arachidonic acid concentrations than before treatment [61]. Furthermore, DHA concentration in the plasma cholesteryl ester fraction has recently been shown to be greater in women (0.53% total fatty acids) compared to men (0.48% total fatty acids) consuming diets controlled for energy and αLNA content, although DHA is a minor component of this plasma lipid pool [62].…”

The Effect of Dietary Intervention Through the Modification of Fatty Acids Composition and Antioxidant Vitamin Intake on Plasma TXB Level in Korean Postmenopausal Women with Hypercholesterolemia

“…On the other hand, in the HRT group, a few fatty acids of serum PL also changed, even though there were no significant changes in their fatty acid intakes. Several studies have suggested that estrogen can affect blood fatty acid composition, but we cannot conclude whether those changes are due to estrogen, or not (33,34). Even now, the effect of estrogen on serum fatty acid composition is controversial, and, as such, requires further research.…”

Metabolism and functional effects of plant-derived omega-3 fatty acids in humans

“…They suggest that the action of oestrogen may therefore explain greater synthesis of EPA and DHA from ALA in young women due to increased activity of the pathway. Ottosson et al reported that oestrogenbased hormone replacement therapy in postmenopausal women resulted in greater plasma di-homo-γ-linolenic and arachidonic acid (AA) concentrations than before treatment [178]. Giltay et al describe greater DHA concentrations in the plasma cholesteryl ester fraction of women (0.53% of total fatty acids) compared with men (0.48% of total fatty acids) after consumption of increased ALA [179].…”