Changes in the binding of angiotensin II to rat placental receptor by estrogen and progesterone.

The effects of estradiol and progesterone on the binding of rat placental angiotensin II receptors were examined. Sex steroid (progesterone estradiol plus progesterone) decreased the total number of rat placental angiotensin II receptors, while sex steroid (estradiol plus progesterone) increased angiotensin levels. Our present results suggest that sex steroids may play an important role in the control of the number of the angiotensin binding sites during pregnancy.