Mammary Carcinogenesis by 3-Methylcholanthrene. IV. Effect of Pituitary Homograft on Mammary-Gland Growth and Tumorigenesis2

Publisher Website
Google Scholar
Abstract
Single pituitary homografts were transplanted subcutaneously into intact female, castrated female, intact male, and orchiectomized male rats subsequently treated with optimal carcinogenic dose of 3-methylcholanthrene (3-MCA). In intact females, a functioning pituitary graft maintained functioning corpora lutea and caused milk secretion. In castrated female, intact male, and castrated male rats, the pituitary graft stimulated the growth of the mammary glands. One of the most significant observations was that prolactin released by the pituitary graft exerted a direct action on the growth of the mammary gland and that this function was independent of the presence or absence of the ovaries and pituitaries. Prolactin released by the pituitary graft, however, had little or no effect on the induction of mammary cancer in these rats when they were treated with 3-MCA. Multiple pituitary grafts (2 to 4) in castrated male rats induced “lactation” but did not increase tumor incidence. It is concluded that the pituitary hormones, especially the lactogenic hormones, involved in mammary-gland growth may not be needed in the development of mammary tumors in 3-MCA treated rats.

This publication has 0 references indexed in Scilit: