Ovarian lipid metabolism modulates circulating lipids in premenopausal women

Context: The premenopausal circulating lipid profile may be linked to the hormonal profile and ovarian lipid metabolism. Objective: Assess how estradiol, progesterone, and ovarian lipid metabolism contributes to the premenopausal lipid profile; and evaluate the acute effects of a common hormonal oral contraceptive (OC) on circulating lipids. Design: Experimental crossover with repeated measures. Setting: Academic hospitals. Patients: Eight healthy, regularly menstruating women. Interventions: Participants underwent periodic serum sampling during a normal menstrual cycle; a standard 21-day, monophasic combined hormonal OC cycle (30 mg of ethinyl estradiol and 150 mg of levonorgestrel per day); menopause simulated by leuprolide acetate (22.5-mg depot); and an artificial menstrual cycle achieved via transdermal estradiol (50 to 300 mg/d) and vaginal micronized progesterone (100 to 300 mg/d). Main Outcome Measures: Primary outcomes included evaluation of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, triglycerides, and the total cholesterol to HDL cholesterol ratio. To estimate the effect of estradiol, progesterone, and ovarian lipidmetabolism, all specimens except those fromthe OC cyclewere analyzed. Subgroup analysis was conducted on the follicular and luteal phases. In a separate analysis, the effect of theOCwas evaluated relative to the normal menstrual cycle. Results: Estradiol was significantly associated with increased levels of HDL cholesterol throughout the menstrual cycle and in the follicular phase. Ovarian effects were associated with reduced lipid levels, especially during the luteal phase. The OC was associated with an increased total cholesterol to HDL cholesterol ratio and triglycerides. Conclusion: Previously unappreciated factors including ovarian lipid metabolism may contribute to the premenopausal lipid profile.