Localization of angiotensinogen in rat liver by immunocytochemistry

Plasm angiotensinogen, the protein precursor of angiotensin, is produced by the liver. The present study investigated the location of angiotensinogen in sections of rat liver using the unlabeled peroxidase-antiperoxidase bridge technique of Sternberger. Specific reaction products of the antibody localization method were most pronounced in the cytoplasm of hepatocytes in the pericentral zone of the liver lobule. Controls, in which antibody was preabsorbed with angiotensinogen, did not form reaction product. The gradient of angiotensinogen observed within liver lobules resembled that demonstrated by metabolic zonation. The distribution of angiotensinogen differed from the scattered distributions found for other plasma proteins.