Effects of an angiotensin II antagonist; [sarcosine, isoleucine] angiotensin II, on blood pressure, plasma renin activity and plasma aldosterone concentration in hypertensive and normotensive subjects taking oral contraceptives.

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Abstract
To examine the involvement of renin-angiotensin-aldosterone system in the etiology of oral contraceptive induced hypertension, normal women (Group I), normotensive (Group II) and hypertensive (Group III) women taking Ovulen (R) were infused with a competitive angiotensin II (AII) antagonist, [1-sarcosine, 8-isoleucine] angiotensin II. The angiotensin II antagonist was infused at a rate of 600 ng/kg per min for 30 min, 1.5 h after i.v. injection of 40 mg of furosemide. Blood pressure was monitored and pre-infusion and post-infusion plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were determined. Pre-infusion PRA and PAC showed no significant differences among these 3 groups. In response to the AII antagonist infusion blood pressure rose in Groups I and II, but blood pressure responses in Group III were variable. Out of the total 6 subjects, 4 had pressor responses and only 1 subject had a significant blood pressure reduction. In both Groups I and II, PRA decreased and PAC rose after infusion of the antagonist. In Group III, PRA decreased to a lesser degree and PAC showed no consistent change. The renin-angiotensin-aldosterone system in hypertensive women on oral contraceptives is different from that of the normotensive users. The pathophysiology of oral contraceptive induced hypertension is not homogenous and angiotensinogenic hypertension is uncommon.