Survival and Function of Auto‐ and Homografts of Adenohypophysial Tissue in the Toad, Bufo Bufo (L)

Abstract

Summary. In the toad, Bufo bufo (L), the survival and function of auto‐ and homografts of the pars distalis of the pituitary gland placed under the median eminence or under the recessus opticus of the brain were studied. The toads were supplied with the grafts after removal of the pars distalis or after hypophysectomy. All autografts were well vascularized and surviving. However, only the autografts under the median eminence receiving a vascular supply from the hypophysio‐portal system appeared normal and exerted functional activities, as judged from the condition of the skin and the length of survival of the recipient. The survival of homografts was limited. Such grafts placed under the median eminence were, however, functional during periods of up to 16 weeks. Homografts placed under the recessus opticus failed to exert the activities studied in the present work. The recipients of homografts at this site did not survive appreciably longer than toads with the pars distalis removed, and their skin showed abnormal keratinization. The observations support the assumption that in amphibians the functional significance of the hypophysio‐portal system is the same as in mammals. The importance of immunological reactions for the function of homografts of this endocrine gland is discussed. Our thanks are due to Mrs. Gunhild Nilsson for her skilled help with the histological work and to Miss Gunnel Christiansson for valuable technical assistance. This work has been supported by a grant from the Rockefeller Foundation.