Effects of a Non‐vasoconstrictor Dose of Phenylephrine on Prostaglandin E2 and Renin Release in Anaesthetized Dogs

Phenylephrine (1 microgram/min) was infused into the renal artery of pentobarbitone anaesthetized dogs. Systemic blood pressure and renal blood flow were monitored. Arterial and renal venous blood samples were collected before and 10 min after the start of the infusion. Plasma prostaglandin E2 concentration and plasma renin activity were measured by radioimmunoassay. This dose of phenylephrine did not affect systemic blood pressure and renal blood flow. However, both prostaglandin E2 and renin secretion rates were increased by the infusion of phenylephrine. These results suggest that renal alpha-adrenoceptors participate in prostaglandin and renin release independent of the changes in systemic blood pressure and renal blood flow.