VASOCONSTRICTOR EFFECTS OF ANGIOTENSIN-II ON THE PULMONARY VASCULAR BED

The systemic presser effects of angiotensin II (ANGII) are well descri bed, whereas relatively little is known regarding its effects on the p ulmonary circulation in humans. Doppler echocardiographic measurements were performed in eight normal volunteers after a 30-min control infu stion (baseline), after sequential 30 min stepwise infusions of ANGII (2, 4, and 6 ng/kg/min), and again 30 min after stopping ANGII therapy . There were significant dose-related increases in mean pulmonary arte rial pressure and total pulmonary vascular resistance, with values ret urning to baseline after stopping ANGII therapy. However, the increase in vascular resistance was proportionately greater for the pulmonary compared with systemic vascular bed, and the difference was significan t at all doses of ANGII. Thus, the pulmonary vasculature exhibited gre ater sensitivity to the vasoconstrictor effects of ANGII in comparison with the systemic vasculature.