BROWN ADIPOSE-TISSUE PROTEINS IMPEDE THYMUS DEVELOPMENT IN RATS

The biological effect of the protein component of hypertrophic brown d ispose tissue (BAT) of ground squirrels on thymus development in immat ure Wistar rats was studied morphologically. It was established that r epeated intraperitoneal injections of BAT proteins produced remarkable regression and hypotrophy in the thymus parenchyma. This was demonstr ated anatomically and histologically by a decrease in the weight of th e thymus treated rats as well as in the size of the cortical areas of lobules and an expansion of their medulla; also by the thinning away o r disappearance of the superficial cortex, a decrease in the number of blasts and immature forms of lymphocytes in mitosis, but an intensifi cation of phagocytosis.