Inhibitory action of somatostatin on cAMP dependent pepsinogen secretion from rat gastric chief cells: involvement of pertussis toxin-sensitive G-protein.

We examined the inhibitory effect of somatostatin on pepsinogen secretion using isolated rat gastric chief cells. Secretin and forskolin significantly increased not only pepsinogen secretion from chief cells but also cellular cAMP accumulation in a dose-dependent fashion. Somatostatin significantly inhibited secretin- and forskolin-induced pepsinogen secretion and secretin-induced cellular cAMP accumulation. However, forskolin-induced cellular cAMP accumulation was not inhibited by somatostatin. The inhibitory effect of somatostatin on secretin-induced pepsinogen secretion was abolished by pretreatment with pertussis toxin, but inhibition of forskolin-, carbachol- and cholecystokinin octapeptide-induced pepsinogen secretion was not. These results suggest that somatostatin inhibits pepsinogen secretion in two ways, one is closely related to the pertussis toxin-sensitive G-protein and the other is not determined.