Regulation of gastric acid secretion in situ by an endogenous activator protein: Studies with activator-specific antibody

Monospecific polyclonal antibody was raised against a homogenous preparation of endogenous activator protein (HAF) for the gastric H+,K+-ATPase system. Antibody was used to assess the regulatory role of the HAF in gastric acid secretion by isolated rabbit glands in situ. Immunohistochemical studies revealed aredistribution of theHAFtowards discrete intracellular zones following stimulation of the glands with histamine. The antibody, when inserted into the stimulated gastric glands by digitonin permeabilization, could effectively block the acid forming ability of the cells. The data offers, for the first time, some concrete in situ evidence for the role of the HAF as an intracellular regulator of gastric H+ transport .