Polyphloretin phosphate temporarily potentiates prostaglandin E2 on the rat fundus, probably by inhibiting PG15-hydroxydehydrogenase

Abstract

Polyphloretin phosphate (PPP), an antagonist of some smooth muscle action of prostaglandins, potentiates the effect of prostaglandin E2 on the rat isolated stomach fundus preparation. No such potentiation could be demonstrated for prostaglandin 15(S) 15 methyl E2 methyl ester, a synthetic analogue of prostaglandin E2. PPP also stimulates the longitudinal muscle of human isolated jejunum to contract. Evidence is produced to show that the potentiation of prostaglandin E2 and the direct stimulant action of PPP are due to inhibition of prostaglandin 15-OH dehydrogenase, an enzyme which inactivates prostaglandin E2 but not 15(S) 15 methyl E2 methyl ester.