Serum leptin concentrations during the menstrual cycle in normal-weight women: effects of an oral triphasic estrogen-progestin medication

Objective: To investigate in normal-weight premenopausal women the relation ship between circulating leptin and serum gonadotropins and gonadal steroid s, during both spontaneous and pharmacologically induced menstrual cycles. Design: Clinical longitudinal study Methods: Two groups of age-matched, normal-weight premenopausal volunteer w omen (groups I and II) were enrolled in this study. Women in group I were f ree of any hormonal treatment, while women in group II were taking a tripha sic estrogen-progestin contraceptive preparation, Blood samples were collec ted daily in both groups after an overnight fast throughout a complete mens trual cycle, Results: In the spontaneously cycling women, serum leptin concentration pos itively correlated with estradiol (P < 0.03) and progesterone (P < 0.05) an d was higher in the luteal than in the follicular phase (P < 0.05). However , a significant (P < 0.03) short-lasting increase in. circulating leptin wa s present in the late follicular phase of all subjects. In the women using hormonal contraception serum leptin remained unchanged throughout the cycle , along with constantly low values of circulating luteinizing hormone and f ollicle-stimulating hormone. Conclusions: In normal-weight premenopausal women serum leptin concentratio ns differ during the menstrual cycle in line with changes in gonadotropin a nd gonadal steroid concentrations, increasing in the luteal phase of the cy cle after a peri-ovulatory peak. These findings suggest a permissive role f or leptin with regard to the functioning of the corpus luteum.