Does progestogen reduction in oral contraception parallel reduced lipid metabolic effects?

Area of Science:

• Endocrinology
• Lipid Metabolism
• Pharmacology

Background:

• Oral contraceptives are widely used for family planning.
• Understanding their impact on lipid metabolism is crucial for women's health.
• Estrogenic and progestogenic components can differentially affect metabolic pathways.

Purpose of the Study:

• To compare the effects of two sequential contraceptive preparations on lipid metabolism.
• To evaluate the influence of ethinylestradiol and varying progestogen doses on serum lipids and lipoproteins.
• To assess the impact on fatty acid composition in serum lecithin and cholesterol esters.

Main Methods:

• Cross-over study design involving twelve young fertile women.
• Administration of two sequential oral contraceptives: Sequilarum and Ovanone.
• Analysis of serum triglycerides, phospholipids, and cholesterol.
• Lipoprotein lipid analysis using ultracentrifugation.
• Gas-liquid chromatography for fatty acid composition of serum lecithin and cholesterol ester.

Main Results:

• Both contraceptive preparations demonstrated predominantly estrogenic effects, increasing serum and VLDL triglyceride levels.
• No substantial influence on HDL cholesterol was observed, suggesting a modifying effect of the progestogen component.
• Changes in serum lecithin's palmitic and stearic acid composition were consistent with previous findings for 17C-alkylated steroids.

Conclusions:

• Sequential oral contraceptives containing ethinylestradiol primarily impact lipid metabolism via estrogenic mechanisms.
• The progestogen component appears to modulate the effects on HDL cholesterol.
• Fatty acid alterations in serum lecithin are a predictable response to these types of steroids.