Abstract
Conflicting evidence has been obtained regarding the ability of the epithelial hypophysis to differentiate and function in heterotopic transplants in amphibia. Blount, 1 using Amblystoma punctatum, failed to obtain differentiation of the epithelial hypophysis independent of the infundibulum. Etkin 2 made successful single and multiple transplants in Rana sylvatica with a minimum of brain tissue, but he made no attempt to remove all possible adherent brain.
The writer, in 1931, removed the hypophysis from 18 specimens of R. sylvatica at the tail-bud stage and transplanted it in the same individual to a location between the right otic vesicle and the hind brain. Care was taken not to include any brain tissue or any entoderm. Eight of these animals gave evidence of function of the hypophysis according to one or more of the criteria enumerated below, although 5 were sacrificed at a stage before evidence of anterior lobe function can be obtained. In the present year similar operations were attempted on 75 R. sylvatica, 30 R. pipiens and 50 A. punctatum. From the experiments of these 2 years serial sections of head, thyroid and gonad-adrenal regions have been studied from 64, 8 and 5 animals of the above species, respectively. In addition, the condition of the hypophysis and the thyroid has been determined at autopsy in 10 A. punctatum, while 30 animals of this species are still alive. For control study records and sections from more than 200 normal, or completely or partially hypophysectomized amphibia, mostly R. sylvatica, were available.
Get full access to this article
View all access options for this article.