The effects of a prostaglandin endoperoxide analogue on canine gastric acid and mucus secretion.

The effects of U-46619, a stable analogue of the prostaglandin endoperoxide PGH2, were studied on canine gastric acid secretion, gastric mucosal blood flow, and secretion of mucus into gastric juice and compared to those of PGE2. U-46619 was approximately four and three times as potent as PGE2 in inhibiting acid secretion and stimulating mucus secretion, respectively. When infused at a low dose, U-46619 inhibited acid secretion directly without causing a decrease in the ratio of mucosal blood flow to volume rate of secretion (R), this effect being similar to that observed for PGE2. However, unlike PGE2, U-46619 when administered in a higher dose caused a decline in R while decreasing acid secretion and mucosal blood flow, suggesting a primary restriction of blood flow. The antisecretory effects of arachidonic acid may be due in part to the endogenous formation of prostaglandin endoperoxides as opposed solely to prostaglandin formation. Considering the antisecretory and mucogenic actions of U-46619, nontoxic analogues of prostaglandin endoperoxides may be of value as antiulcer agents.