The effects of angiotensin II and indomethacin on the pulmonary arterial prostaglandin E levels and pulmonary circulation in dogs.

We studied whether pulmonary arterial levels of plasma prostaglandin E rose following pressor effects of angiotensin II in the intact dogs. Furthermore, the modulation by indomethacin of the effect of angiotensin II, PGF2 alpha, and PGE1 on pulmonary circulation was evaluated. Pulmonary arterial plasma PGE levels rose significantly from 0.52 +/- 0.10 (SE) ng/ml to 0.85 +/- 0.07 by the infusion of angiotensin II. This increase was not observed when indomethacin was given. The rise in pulmonary arterial pressure and total pulmonary resistance by angiotensin II was augmented significantly with pretreatment of indomethacin. These results showed that there was an augmentation of the pulmonary vasoconstrictor action of angiotensin II as indomethacin blocked an increase of pulmonary arterial PGE level. Thus, it was suggested that prostaglandins (especially PGE) modulated the pulmonary vasoconstrictor effects of angiotensin II.