Comparative effects of PGD2 and PGE2 in the regional circulation of the cat

The peripheral vascular effects of PGD2 and PGE2 were investigated in the anesthetized cat. PGD2 and PGE2 caused dose-related decreases in hindquarters and renal perfusion pressure whereas intestinal responses to these substances were divergent. Since regional blood flows were held constant with a pump, changes in perfusion pressure directly reflect changes in hindquarters, renal and intestinal vascular resistance. PGD2 and PGE2 had similar vasodilator activity in the hindquarters vascular bed. In the renal vascular bed, the dilator response to high doses of PGD2 was greater than to PGE2 whereas the low dose of PGE2 produced a greater reduction in renal vascular resistance. In the intestinal vascular bed, bolus injections and infusion of PGE2 decreased vascular resistance whereas PGD2 had biphasic effects possessing an initial vasoconstrictor component. These data demonstrate that PGD2 and PGE2 have significantly vasoactivity in the regional circulation. In addition, the relative vasodilator effects of PGE2 are organ dependent and the effects of PGD2 depend on both organ and dose in the cat.