Comparison of the effect of somatostatin on gastrointestinal function in the conscious and anaesthetized cat and on the isolated cat pancreas.

1. Somatostatin, 10 microgram kg-1 hr-1, inhibited gastric acid and pepsin secretion stimulated by pentagastrin, 8 microgram kg-1 hr-1, in conscious and anaesthetized cats with chronically implanted gastric fistulae. In the acutely surgically prepared anaesthetized cat, Somatostatin inhibited pepsin secretion but produced little inhibition of gastric acid secretion or mucosal blood flow. 2. Secretin stimulated pancreatic juice volume was not significantly reduced in acutely prepared anaesthetized cats, but there was a limited reduction of cholecystokinin-pancreozymin stimulated pancreatic amylase secretion and gall bladder contraction. 3. Somatostatin had neither stimulatory nor inhibitory effects on electrolyte and amylase secretion in the isolated saline-perfused cat pancreas. 4. The results suggest that some of the effects of Somatostatin may depend on the interaction on the target cell of other factors, nervous or humoral which may vary in different experimental preparations.