Effect of somatostatin and its analogs on histamine-stimulated cAMP production in isolated guinea pig gastric glands.

The effect of somatostatin-14 (ss-14), somatostatin-28 (ss-28), and [D-trp8]somatostatin-14 ([ D-trp8]ss-14) on both histamine-stimulated cellular cAMP production and [3H]-cimetidine binding on plasma membranes in isolated guinea pig gastric glands was investigated. These three peptides partially inhibited (approximately 50% maximally) the increase of cAMP production stimulated by histamine. There was no inhibition of [3H]-cimetidine binding on plasma membranes from these isolated gastric glands. These results indicate that somatostatin acts directly on parietal cells and inhibits histamine-stimulated cAMP production with no influence on H2 receptor in histamine stimulated gastric secretion. Inhibitory potency of somatostatin and its analogs against histamine-stimulation may be equal at the cellular level.