Pituitary transplantation: Part 1. Successful reconstitution of pituitary-dependent hormone levels.

Neonatal or adult pituitary glands were transplanted to the median eminence of adult rats of the same or a histoincompatible inbred strain. The hormonal status of 39 transplanted rats and of control animals was evaluated by serial determination of serum prolactin and thyroxine. Grafts of neonatal tissue to adults of the same strain resulted in normal postoperative hormone levels. This indicates not only that pituitary grafts had survived, but also that the transplants were under hypothalamic control. Grafts of adult tissue were less successful. The prolactin value was lower, but still within the normal range, whereas the thyroxine value was lower than normal, suggesting that viable pituitary tissue had survived but was not under hypothalamic control. Transplantation across a histocompatibility barrier was uniformly unsuccessful. Postoperative prolactin levels were low and thyroxine levels were not significantly different from those in hypophysectomized controls.