Inhibitory effect of misoprostol on gastric acid secretionin vitro

The synthetic PGE₁ analog, misoprostol, was shown to have a marked inhibitory effect on gastric secretion as determined in the isolated gastric fundus from immature rats. It inhibited both the unstimulated and pentagastrin-stimulated acid secretion at 10^–7–10^–4 molar concentrations. Its effect was different from that of PGE₁ and PGE₂, which did not affect basal acid secretion (up to 3×10^{–5 M}), although they inhibited to the same extent as misoprostol the pentagastrin-induced acid secretion. When given by mucosal application, misoprostol (10^–7–10^–5 M) behaved similar to the mast cell stabilizer, compound FPL 52694, but its maximum reduction response was only 50%. The above data suggest that misoprostol has additional antisecretory mechanisms of action not shared by the classical natural prostÃglandins.Supported by a grant from the C.N.R., Rome.