Action of somatostatin on stomach, pancreas, gastric mucosal blood flow, and hormones

In dogs gastric secretion induced by tetragastrin and pancreatic secretion induced by secretin and/or cholecystokinin were inhibited by somatostatin at doses of 0.06-1 microgram X kg-1 X h-1 and 0.06-1 microgram X kg-1 X 0.5 h-1, respectively. Inhibition was a linear function of the logarithm of dose. Basal and 2-deoxy-D-glucose-induced gastric acid secretion was also significantly inhibited by low doses of somatostatin. Results in this study differ from those reported previously by clarifying the action of somatostatin as follows. 1) The inhibitory effect of somatostatin on pancreatic protein secretion was significantly greater than that on water and bicarbonate production. Somatostatin was more effective on cholecystokinin- than secretin-induced pancreatic secretion. 2) Although gastric mucosal blood flow (MBF) was affected by somatostatin, the reduction of MBF was not the primary mechanism responsible for its inhibitory action. 3) The low doses of somatostatin used in this study significantly inhibited gastric and pancreatic secretion without affecting the basal plasma concentrations of insulin, glucagon, growth hormone, gastrin, or secretin in the dogs, suggesting that the inhibitory action was not mediated by changes or reduction in plasma concentration of these hormones.