Prostaglandin synthesis inhibition reverses the gastric antisecretory activity of somatostatin in anaesthetized rats.

The inhibitory action on somatostatin (ST) on the spontaneous and stimulated (pentagastrin 18 micrograms/kg/h i.v. and histamine 5 mg/kg/h i.v.) gastric acid secretion and its modification after pretreatment with an inhibitor of endogenous prostaglandins biosynthesis (indomethacin 5 mg/kg i.v.) has been studied in the anaesthetized rat. ST 30 micrograms/kg/h i.v. inhibits basal and stimulated gastric acid secretion. In the presence of indomethacin the inhibition elicited by ST on basal and pentagastrin induced gastric acid secretion was partially attenuated, whereas in the histamine group the inhibitory action was totally abolished. The antagonism elicited by indomethacin was not surmounted by increasing (X 3.3) the dose of ST. These findings suggest that endogenous prostaglandins may be involved in the mechanism by which ST exerts its antisecretory effect in this model.