Activation of histidine decarboxylase by H2-receptor blockade: mechanism of action.

1 Treatment with histamine H2-receptor antagonists, which inhibit basal acid secretion was found to activate rat stomach histidine decarboxylase. At the same time the serum gastrin concentration was greatly increased. 2 In antrectomized rats neither the enzyme activity nor the serum gastrin concentration was affected by the treatment. 3 In analogy with previous observations on other inhibitors of acid secretion we suggest that the H2-receptor antagonists stimulate gastrin release through their effect on acid secretion and that the raised serum gastrin level is responsible for the enzyme activation.