Histamine formation in rat gastric mucosa and lung after injecting reserpine or adrenaline.

1. In rats the effect of reserpine, adrenaline and gastrin on the histamine forming capacity (HFC) of gastric mucosa and lung was examined.2. Intraperitoneal reserpine as well as subcutaneous adrenaline produced a great increase in HFC of gastric mucosa but a great decrease in HFC of lung. After reserpine the HFC of lung was almost abolished.3. As the HFC changes produced by reserpine occurred also after demedullation of the suprarenals--the changes in the mucosa were in fact accentuated--release of the medullary hormones by the reserpine does not account for these changes.4. Subcutaneous gastrin caused a great increase in HFC of the gastric mucosa but did not affect the HFC in lung.5. The possible role of release of gastrin and corticosteroids for the reserpine-induced HFC changes is discussed because it is known that reserpine releases gastrin and corticosteroids and that cortisone produces HFC changes in gastric mucosa and lung.