CIRCULATING NITRITE/NITRATE LEVELS INCREASE WITH FOLLICULAR DEVELOPMENT - INDIRECT EVIDENCE FOR ESTRADIOL MEDIATED NO RELEASE

Ovarian dysfunction as well as impaired release of endothelium-derived nitric oxide (NO) is associated with increased incidence of cardiovascular disease in postmenopausal women. Estrogen replacement therapy in postmenopausal women has a cardioprotective effect. Hence, using follicular development (FD) phase of the menstrual cycle of normal women (n=7) and of patients undergoing in vitro fertilization (n=16), we tested whether ovarian/sex hormones modulate NO-release. Levels of nitrite/nitrate (stable metabolites of NO), 17 beta-estradiol (E), progesterone (P), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured in serum collected during FD-phase. Serum nitrite/nitrate levels increased (p<.01) with the normal, as well as hormonally-induced FD and correlated with increases in serum E levels (r(2)=0.67; p<.Ol), but not with P, FSH and LH (p>.05). Post-ovulatory increase in P and LH levels decreased serum nitrite/nitrate levels (p<.05), even in presence of high E levels. In conclusion, nitrite/nitrate increase with follicular development, an effect that is potentially mediated by E induced NO release. (C) 1994 Academic Press, Inc.