CIRCULATING LEVELS OF NITRIC-OXIDE IN FERTILE WOMEN IN RELATION TO THE MENSTRUAL-CYCLE

Objective: To investigate nitric oxide (NO) production in the two phas es of normal menstrual cycle. Design: Prospective clinical study. Sett ing: Normal human volunteers in an academic research environment. Pati ent(s): Fifteen normally cycling women. Intervention(s): Follicle grow th monitoring by ultrasound, serum, and plasma sampling in the midfoll icular phase, at ovulation, and in the midsecretory phase. Main Outcom e Measure(s): Plasma concentration of NO stable oxidation products and serum concentrations of E(2) and P. Result(s): Plasma concentration o f NO metabolites resulted higher in the follicular phase with respect to the secretory phase and peaked at midcycle. Conclusion(s): The resu lts strongly support the existence of an E(2) control of NO production and release. The significant reduction in NO metabolites observed in the secretory phase suggests a possible opposing action of P on either NO production or release.