Plasma Aldosterone and Renin Activity during the Menstrual Cycle1

Plasma aldosterone concentration and renin substrate have been measured in the fasting supine state daily throughout five normal menstrual cycles. Three out of the four subjects studied had a clear-cut peak of plasma aldosterone during the mid or late luteal phase. Increases in renin activity accompanied or immediately preceded the plasma aldosterone peaks in two out of the four cycles in which renin activity was measured. Renin substrate did not change during the cycles. It is possible that a progesterone induced luteal phase increase in renin activity is responsible for the alteration in plasma aldosterone.