Immunoradiometric assays of total renin and gonadotropins in serum during the menstrual cycle

The contribution of the ovary to the circulating total renin pool is linked to its secretory activity in relation with its reproductive function. In a longitudinal study of 13 normal women, total renin levels measured in serum by an immunoradiometric assay were lower in the midfollicular phase (180 +/- 59 pg/ml) than in the midluteal phase (291 +/- 100 pg/ml). Peak levels were encountered 1 day after the luteinizing hormone (LH) surge (375 +/- 97 pg/ml). Rapid circhoral fluctuations were observed in all periods of the cycle, unrelated to the LH pulses. In case of ovarian function inhibition (induced by gonadotropin-releasing hormone agonists), total renin levels were lower than in the midfollicular phase (126 +/- 56 pg/ml). Low levels also were encountered in the prepubertal period (153 +/- 89 pg/ml). Very high levels (17,600 +/- 11,400 pg/ml) were found in follicular fluids from stimulated cycles. These results show that circulating total renin levels follow a complex pattern in which LH, but possibly also follicle-stimulating hormone and gonadal steroid hormones (estradiol and progesterone), may play a role.