Renin release induced by a nonvasoconstrictor dose of phenylephrine is independent of the renal prostaglandin system in anesthetized dogs.

We examined the relationship between prostaglandin (PG) production and renin release induced by a nonvasoconstrictor dose of an alpha-agonist, phenylephrine, in anesthetized dogs. Intrarenal infusion of phenylephrine (1 microgram/min) did not affect systemic blood pressure or renal blood flow, but increased the renin secretion rate about twofold. The effect of phenylephrine on renin release was abolished by the intrarenal infusion of the alpha-antagonist phentolamine (50 micrograms/min), but was not affected by the intravenous administration of the PG synthetase inhibitor indomethacin (5 mg/kg). Urine flow and urinary sodium excretion rate were not altered by phenylephrine. These results suggest that a nonvascular and nontubular alpha-adrenoceptor mechanism, which is independent of the renal PG system, may be involved in renin release.