The Relation of the Hypophysis to the Growth of Malignant Tumors: IV. A Study of the Influence of Nutritional Factors on Walker Tumor 256 in Relation to the Effect of Hypophysectomy

Since pituitary ablation has been shown to influence the rate of growth of transplanted (1–4) and autogenous (5) rat tumors, several investigators (6, 7, 8) have made an effort to define the factors by which this effect is produced. The numerous physiologic and anatomic changes which follow hypophysectomy contribute to make the problem complex. The present study is concerned with an appraisal of nutritional factors. McEuen and Thomson have previously observed the influence of degrees of starvation on the rate of growth of Walker tumor 256 and compared their results with the same tumor in hypophysectomized animals. They concluded that starvation may retard tumor growth as much as hypophysectomy. From the data presented, however, there was some question as to the validity of this conclusion (7, 5). We have attempted to restudy the question, using a technic of feeding which we believe increases the accuracy of the experiment. Methods Male rats about four months of age (150–180 grams) were inoculated with Walker tumor 256. The donor tumors were second, third, and fourth generation transplants in our hands from a tumor-bearing female of generation 154–B obtained through the courtesy of Dr. F. C. Wood of the Institute of Cancer Research of Columbia University. Solid tissue grafts were implanted by the trocar method into the left axillary region, through a skin incision in the groin. Ten days to two weeks later the animals were paired prior to removal of the pituitary in one mate. The operations were performed through a neck incision, pains being taken to avoid the nasopharynx. Completeness of removal was judged by the development of genital atrophy, and at death by direct inspection of the pituitary fossa from above.