Effect of prostaglandin I2 and related compounds on vascular permeability response in granuloma tissues

The effects of prostaglandin I₂, 6-ketoprostaglandin F_1α, prostaglandin E₁ and thromboxane B₂ on the vascular permeability response in rat carrageenin granuloma were studied with the aid of ¹³¹I- and ¹²⁵I-human serum albumin as indicators for the measurement of local vascular permeability.A single injection of 5 μg of prostaglandin I₂ methyl ester or I₂ sodium salt into the locus of the granulomatous inflammation elevated local vascular permeability 2.0–2.5 times over the control within 30 min. The potency was equal to that of the positive control prostaglandin E₁ which has been known to be the most potent mediator in this index among several candidate prostaglandins for chemical mediator of inflammation. The other prostaglandin and thromboxane B₂ tested were essentially inactive.