The effect of brocresine (NSD-1055) on the histidine decarboxylase activity in the rat gastric mucosa

Abstract

The effect of the histidine decarboxylase inhibitor brocresine (NSD-1055) on the specific histidine decarboxylase in the gastric mucosa was investigated in rats. The inhibiting potencies of brocresine were compared after oral and intraperitoneal administration with and without 2-deoxy-d-glucose. Furthermore, different doses of brocresine were added directly to an incubation medium containing an homogenate of the gastric mucosa of untreated animals. The gastric histidine decarboxylase of the brocresine-pretreated animals was not inhibited. Addition of brocresine to the incubation medium produced a dose dependent blockade of the enzyme. 50% inhibition was accomplished by a concentration of 1·4 times 10−6M. The results demonstrated an inhibition of the rat stomach histidine decarboxylase in vitro, but not in vivo, indicating the inability of brocresine to interfere with the biosynthesis of histamine in the rat stomach.