Differential regulation of membrane receptors sensitive to histamine (H2-type), isoproterenol (beta 2-type) and glucagon-like peptides by the somatostatin analogue Sandostatin in rat gastric glands.

The potential use of somatostatin-14 and its long lasting analogue Sandostatin as antiulcer agents led us to study the functional properties of these peptides on the histamine H2-receptor H2R adenylate cyclase system in gastric glands isolated from the rat fundus. The action of the two peptides has also been compared on membrane receptors sensitive to isoproterenol and the truncated glucagon-like peptide TGLP-1. The data indicate that somatostatins inhibit selectively H2R and TGLP-1 receptor activity with similar potencies and kinetics, suggesting that the two peptides share the same receptor pool coupled with the Gi subunits of adenylate cyclase. Somatostatin-14 and Sandostatin have no evident action on the beta 2-type adrenergic receptor beta 2R. Therefore, the higher potency of Sandostatin compared to somatostatin-14 in inhibiting acid secretion is probably related to an increased stability of the analogue in vivo.