Plasma renin activity, plasma renin substrate and urinary aldosterone excretion in the menstrual cycle in relation to the concentration of progesterone and oestrogens in the plasma.

Abstract

ABSTRACT The relative importance of endogenous progesterone and oestrogens on the rise in plasma renin activity and urinary aldosterone excretion in the luteal phase of the menstrual cycle has been investigated in two groups of young women. One group (luteal group) had plasma progesterone levels of 7–19.5 ng/ml (mean 12.3; sem 1.3) in the second half of the cycle. The other group (luteal failure group) had plasma progesterone levels of 1.5–3.0 ng/ml, (mean 2.1; sem 0.16), on the corresponding days in the second half of the cycle. The plasma oestrogen levels and the oestriol excretion did not differ between the groups at any stage of the cycle. In the luteal group the normal increase in plasma progesterone and plasma oestrogens and in oestriol excretion was accompanied by a doubling in plasma renin activity and urinary aldosterone excretion, whereas the plasma renin substrate levels did not change significantly. In the luteal failure group, no significant increase was found in either plasma renin activity or in urinary aldosterone excretion, in spite of the unchanged plasma oestrogen levels and oestriol excretion. In this group too the plasma renin substrate levels showed no change from the first to the second half of the cycle. It is concluded that the rise in plasma renin activity, plasma angiotensin II concentration and urinary aldosterone excretion in the luteal phase of the normal menstrual cycle is caused by increased progesterone production.