Effect of estrogen and progesterone treatment on the depressor response to prostaglandin E2 in ovariectomized women.

The effect of exogenous estrogen and progesterone on the response of the systemic arterial pressure to prostaglandin E2 (PGE2) was studied in 15 ovariectomized women. All experiments were performed on the 7th postoperative day. Arterial blood pressure was measured in all women in supine position at one minute intervals by an automatic recorder. PGE2 infused intravenously in all subjects for 10 minutes. Ten of the women who were given intramuscular injections of either estradiol benzoate (10 mg) or inert vehicle 60-65 hours before the experiment, showed a significant decline in both systolic and diastolic blood pressure during the PGE2 infusion. In contrast, the remaining of the women who were injected with progesterone intramuscularly also 60-65 hours before the experiment, did not present any significant alterations in blood pressure during or after the infusion of PGE2. These results suggest that, in ovariectomized women, progesterone treatment prevents the depressor response to PGE2. This may be due to increased inactivation of PGE2 by various tissues.