Function of Pituitary Grafts in Mice. ∗

It is only very recently that anterior pituitary tissue has been successfully grafted. Hohlweg and Junkmann, 1 Gardner and Hill, 2 and Haterius, Schweizer, and Charipper 3 have all obtained viable grafts with varying success. May 4 cited a slight increase in body size and a repair of the testes as evidence of function in 2 hypophysectomized rats bearing intraocular pituitary implants obtained from new-born rats.

In the mouse a genetical uniformity of host and donor is necessary for successful intra-testicular grafts of pituitary tissue (Strong 5 ). Will the anterior lobe become functional when implanted in the testis where pressure is slight and vascularization of the graft normal? A large amount of data has been collected which very definitely establishes function of such grafts.

Brief notes on only 2 representative cases are here presented. Intra-testicular grafts become well established and vascularized within 3 weeks. Grafts which have been in the host animal for shorter periods have not been examined. Mouse 103 received an intra-testicular graft of a sister pituitary when 50 days old. The animal was hypophysectomized at 73 days of age and was killed 120 days later. The mouse ejaculated when killed with gas just as many normal male mice do. The seminal vesicles were of normal size and were filled with secretion. The testes were normal in size, and pituitary tissue could not be observed macroscopically in the sella. Serial sections of the sella showed a very tiny cluster of pituitary cells. The fragment, measuring not more than 1.5% of the volume of a normal mouse pituitary, consisted largely of intermediate and posterior lobe tissue. Such a small piece of pars anterior did not maintain the gonads of controls and other experimental animals. Our data show that somewhat more than 5% of the anterior lobe (exclusive of posterior and intermediate lobes) must be left in the sella in order to maintain the gonads. Such animals may be, therefore, considered as physiologically hypophysectomized as sexual activity and adrenal cortex are not maintained normally.