Demonstration of specific E-type prostaglandin receptors using enriched preparations of canine parietal cells and [3H]misoprostol free acid.

High-affinity, E-type prostaglandin binding sites in enriched canine parietal cell preparations were identified with [3H] misoprostol free acid, a prostaglandin E1 analogue. Saturable, reversible, and highly stereospecific binding was identified, with approximately 8,000 binding sites per cell. Prostaglandin I and F bound weakly, and cimetidine and histamine did not bind. The results indicate that [3H] misoprostol free acid binds to E-type prostaglandin receptors, which suggests that the ulcer-healing inhibition of gastric acid secretion by misoprostol results from its interaction with a specific E-type prostaglandin receptor.