Nucleoside triphosphatase activity in the breast.

Abstract

The localization of plasma membrane-bound adenosine triphosphatase (ATP-ase) and uridine triphosphatase (UTPase) has been studied in fibrocystic mastopathy, papilloma of the ducts, fibroadenoma, and mammary carcinoma. Enzymatic activity was found to be confined to the plasma membrane; no nuclear or intracytoplasmic activity was observed. In cases of benign mammary changes, there was no difference concerning location and intensity between ATPase and UTPase activity; the surfaces of both myoepithelial and epithelial cells displayed enzymatic activity, while no positive reactions were obtained in the basement membrane and on the cell surfaces facing the lumina. In carcinomas, UTPase activity remained unchanged, while ATPase was restricted to certain parts of the plasma mebrane or the surface of intracytoplasmic lumina. The decrease of membrane-bound ATPase activity in carcinomas might be of use in diagnosis of cancer.