Abstract
Summary 1. The influence of an autonomous, transplanted “mammotropic” pituitary tumor (Furth, MtT.F4) which secretes large amounts of prolactin, STH and ACTH, was tested on mammary lobulo-alveolar (L-A) growth in adreno-ovariectomized (doubly operated) Fischer rats. The MtT.F4-trans-plant stimulated extensive mammary L-A growth in intact or doubly-operated rats. Intact tumor bearing rats showed intense mammary secretion, while doubly operated tumor-bearing rats revealed only slight amounts of mammary secretion. The average weight of MtT.F4 transplants in doubly operated rats was higher than in intact controls. 2. Completeness of adrenalectomy and ovariectomy was verified, as follows: (a) 9 control doublyoperated rats failed to survive more than 15 days after withdrawal of saline; also examination of the experimental rats after sacrifice failed to reveal any presence of adrenal remnants (b) vaginal smears did not indicate the presence of estrogen. It is concluded that full mammary L-A growth can be induced following adreno-ovariectomy in Fischer rats by prolactin and STH released from a MtT.F4 tumor. We express our sincere appreciation to Dr. Jacob Furth and Dr. Untae Kim, Department of Pathology, College of Physicians and Surgeons, Columbia University, for supplying “mammotropic” pituitary tumors; and to Roger Deuben and T. E. Staley for technical assistance.