The Effect of Prostaglandin Ax on Renin and Aldosterone in Man

Blood pressure, pulse rate, plasma aldosterone (PA), renin, and cortisol were monitored during graded intravenous infusions of prostaglandin A, (PGA,), 0.075-0.6 p%/k% min", alone and superimposed on angiotensin II (A II) administration in fire normal men. The infusions of PGA, did not affect Mood pressure, but did progressively increase tbe pulse rate up to 15.2 ± 2.0 (SEM) beats/ min at the highest prostaglandin dose (0.6 ^g/kg min '). Both PA and plasma renin activity (PRA) increased in a dose-related fashion in response to the prostaglandin infusions. Aldosterone increased from a control of 4.8 ± 0.4 to 20.7 ± 1 . 2 ng/dl and PRA increased from 0.9 ± 0.1 to 5.4 ± 0.4 ng/ml h r 1 at the dose of 0.6 jig/kg min '. The correlation between the aldosterone and renin values was r 0.85, P < 0.001. In separate experiments, acute volume expansion with 2 liters of saline did not affect the increase in renin activity induced by exogenous prostaglandin. A II (5 ng/kg min'I increased aldosterone and blood pressure and decreased the pulse rate. Tbe bemodynamic effects were progressively reversed by tbe superimposed prostaglandin infusions, but the observed changes in renin and aldosterone concentrations were not further altered. Tbe PA response to A II infusions was not influenced by indomethacin pretreatment. Prostaglandin A (infusion) appears to have a direct effect on renin release in man.