Plasma renin activity and plasma aldosterone during the normal menstrual cycle.

Six normal women were studied under metabolic balance conditions during the menstrual cycle. Plasma renin activity (PRA) and plasma aldosterone were estimated throughout the cycle under standardized, uniform conditions with sensitive radioimmunoassays. There is a linear increase in PRA and plasma aldosterone during the luteal phase of the cycle provided ovulation occurs. If ovulation fails, no rise is seen in either parameter. Thus, a functioning corpus luteum seems to be essential for the production of these hormonal changes.