Renal vascular effects of endoperoxide analogs, prostaglandins, and arachidonic acid

Renal vascular responses to analogs of prostaglandin H2(PGH2) were investigated in anesthetized dogs. The analogs were potent renal vasoconstrictors whose actions were not affected either by indomethacin or by alpha-adrenergic or angiotensin antagonists. The constrictor activity of the analogs approximated that of norepinephrine. Responses to PGD2 were also obtained. This prostaglandin, previously thought to be inactive, was found to cause renal vasodilation similar to that caused by PGA2. Responses to the prostaglandin precursor, arachidonic acid, were of two types. In some animals, the response was marked vasodilation, whereas in others transient vasoconstriction preceded the vasodilation. These studies demonstrate that PGH2 analogs are potent renal vasoconstrictors and that PGD2 possesses renal vasodilating properties. In addition, it is suggested that the rapid vasoconstrictor portion of the arachidonate response may represent effects of endogneously produced PGH2.