Acute Inhibition of Vascular Angiotensin Sensitivity by Theophylline in Human Pregnancy

Abstract

In order to find a substance which restores the increased angiotensin sensitivity in women considered to be at risk of developing pregnancy-induced hypertension (PIH), the effect of theophylline on angiotensin sensitivity was examined. In 16 normotensive pregnant women with an increased angiotensin sensitivity, intravenous application of 208 mg of theophylline resulted in a significant decrease in vascular responsiveness to angiotensin II (p<0.001). The angiotensin pressor dose (APD) increased from 6.8 ± 2.4 to 11.7 ± 5.6 ng.kg^−l. min⁻¹ (mean ± 1 SD). In the control group of 10 non-treated women, APD slightly decreased. It is suggested, that the effect of theophyline on vascular angiotensin sensitivity is due to an intracelular accumulation of cyclic AMP in the vascular smooth muscle.