Autoradiographic localization of Prolactin Receptors in 7,12-Dimethylbenz[ a]anthracene-Induced Rat Mammary Carcinoma

Abstract

Prolactin receptors were localized by autoradiography in 7,12-dimethylbenz[q]anthracene (DMBA)-induced mammary tumors from rats by incubation of tumor slices with [¹²⁵I]ovine prolactin. Specific prolactin binding was confined to tumor cells, and nonspecific binding was present in alveolar spaces and connective tissue. In some tumors, all cells contained receptors; in others, up to one-half the cells remained unlabeled. These results suggested that variation in receptor content in DMBA-induced mammary tumors may be caused by two distinct populations of cells-one which contains receptors and another which possesses very few receptor sites or none at all.