Localization of kallikreins in the human parotid gland and in the human kidney: a comparative study of immunohistochemistry and enzyme histochemistry

Abstract

Kallikreins were localized in the human parotid gland and in the human kidney from two different aspects of the enzyme: the enzyme antigenicity and the enzyme activity. In the human parotid gland, the kallikrein antigenicity and the enzyme activity were identical in their locations in the ductal cells. In the human kidney, however, the enzyme activity was revealed in the proximal tubule without any corresponding kallikrein antigenicity. Therefore, this activity may be due to esterases other than kallikreins. The Kallikrein antigenicity was found to be located in the basement membrane of tubules, in the interstitium as well as in some granules of the proximal tubule. These results are compatible with tissue kallikreins being formed in the ducts of the human parotid gland and suggest that circulating tissue kallikreins in the plasma are deposited in the human kidney.