STUDIES ON THE PHYSIOLOGY OF LACTATION. VII. LACTATION IN THYROIDECTOMIZED RATS AND GUINEA PIGS1

A considerable amount of progress has been made since the original studies on the lactogenic hormone of the anterior pituitary by Strieker and Greuter (1), Corner (2), and Nelson and Pfiffner (3, 4), toward an understanding of the physiology of milk secretion. These and other confirmatory studies were made on animals with intact hypophyses and thoroughly demonstrated the relation of the anterior lobe to the initiation of lactation. The ablation of the pituitary in lactating animals demonstrated the necessity of that gland for the maintenance of milk secretion. See Nelson (5) for a review of these studies. It was reasonable to suppose that the administration of lactogenic hormone to hypophysectomized animals would result in the initiation of lactation. However, the results of such studies have been conflicting. Lyons, Chaikoff and Reichert (6) and McPhail (7, 8) reported the initiation of lactation in hypophysectomized dogs, ferrets, and cats while Selye, Collip and Thomson (9) were unable to do so in the ...