A rat gastric mucosal preparation for studying agents which affect the in vitro production of prostanoids.

A convenient and reproducible method for measuring the production of prostanoids from either the rat gastric mucosa or whole corpus tissue is described. Use of selective radio-immunoassay was employed to measure production of 6-keto- PGF1 alpha, the stable hydrolysis product of PGI2, and PGE2. The mucosal tissue generated approximately 10 times more 6-keto-PGF1 alpha than PGE2. Gastric muscle tissue, however, produced 2-3 times more 6-keto-PGF1 alpha than the mucosa. Exogenous arachidonic acid was found to elevate the amount of both prostanoids although the rate of formation of 6-keto-PGF1 alpha appeared to be less than that of PGE2. A possible explanation for this was that PGE2 production, in part, was non-enzymic. Mepacrine, a phospholipase inhibitor, was found to inhibit both the control amounts of 6-keto-PGF1 alpha and the increased production of this prostanoid due to exogenous phospholipase activity. The generation of prostanoids was also inhibited by indomethacin in a concentration-related manner which suggested that the method is suitable for screening non-steroidal anti-inflammatory agents in vitro or ex vivo. Preliminary results with the above method have been reported elsewhere.