Antagonism of arachidonic acid hydroperoxide on isolated gastrointestinal tissues as a measure of the inhibition of prostaglandin biosynthesis.

Arachidonic acid hydroperoxide (AAP)-induced contractions of the isolated guinea pig ileum and rat stomach fundus are inhibited by suprofen [alpha-methyl-4-(2-thienylcarbonyl) benzeneacetic acid], indomethacin, phenylbutazone, and acetylsalicyclic acid in descending order of activity. This effect is highly specific, since prostaglandins (PG) and various agonists of gastrointestinal smooth muscle are not, or only weakly antagonized by these four compounds, whereas various compounds, including narcotic analgesics, are inactive versus AAP. The antagonism of AAP-induced contractions of the isolated rat stomach fundus is a valuable test system for inhibitors of PG biosynthesis.