Persistence of Pituitary Grafts in the Testis of the Mouse

Abstract

Heterografts of fresh anterior pituitary tissue have been found to induce both physiological and structural changes, particularly in the gonads. Most implants have been made intramuscularly or subcutaneously. The fate of such implants has either remained unknown or they have been found to undergo necrosis and absorption. Many investigators have found the testis to be a favorable site for ovarian transplants. In some current experiments with mice we have found a very high percentage of successful ovarian grafts in the testis. It was decided to investigate the possibility of anterior lobe tissue becoming more or less permanently established in testicular tissue.

Mice from 22 to 50 days old, and from highly inbred strains, were used.† Littermate brothers or sisters were used as donors. In 12 mice one pituitary was implanted in one testis, and in one animal one pituitary was placed in each testis. The host animals were killed 3 to 12 weeks after implantation. The testes in which grafts had been made were sectioned serially and stained with modified Mallory's triple stain or hematoxylin and eosin. Pituitary tissue was found in the testes of 11 of the 13 mice which were killed. A well-established graft was found in each testis of one animal (1N—Table 1). In the 2 unsuccessful cases the hosts′ testes had undergone severe necrosis.

Intermediate lobe tissue persisted in most of the grafts, but not as uniformly as anterior lobe tissue. The pars nervosa consistently degenerated. Pars intermedia and pars anterior cells were easily recognizable (Figs. 1 and 2), as well as the normally distinct cleft between the 2 tissues. The anterior lobe tissue was, in all cases, very well vascularized, and appeared normal in arrangement, structure, and types of cells.