STUDIES ON GROWTH HORMONE SECRETION IN RATS WITH THE HYPOPHYSIS AUTOTRANSPLANTED TO THE KIDNEY CAPSULE

Abstract

ABSTRACT The secretory capacity of the pituitary gland, autotransplanted to the kidney capsule, was studied with special regard to the secretion of growth hormone (GH). Body weight, body length, tibial epiphyseal width and the mammary gland development after testosterone stimulation were studied. Body growth and tibial epiphyseal width were markedly reduced in the rats with transplanted hypophysis, but not as much as in the hypophysectomized controls. After injections of 0.25 mg testosterone propionate daily for 10 days, only a few groups of alveoli were seen in the mammary glands of the transplanted rats. These observations show that there is a considerable deficiency of GH in rats with the pituitary gland autotransplanted to the kidney capsule. However, the development of a few alveoli in the mammary glands is in favour of the theory that a small amount of GH is secreted from the transplanted pituitary tissue. Injections of a purified vasopressin preparation (Pitressin) in the rats with autotransplanted hypophysis did not influence body growth, tibial epiphyseal width or mammary gland development. Further, no effect of Pitressin was seen on the tibial epiphyseal cartilage of rats with intact pituitary gland as has been reported by Del Vecchio et al. (1958) and Hiroshige & Itoh (1960). These experiments therefore do not support the view that vasopressin acts as a GH releasing factor.