STUDIES ON THE FAT-MOBILIZING FACTOR OF THE ANTERIOR PITUITARY GLAND SUPPRESSIVE ACTION OF THYROXIN

Abstract

A thyrotropic hormone preparation (TTH) produced three effects: increased thyroid activity (hyperthermia and increased BMR); fat mobilization (histologically demonstrable neutral fat in liver, kidneys and skeletal muscles including external ocular muscles) and exophthalmos (progressive retro-orbital deposition of lymphocytes and mast cells, followed by metachromatic mucinous intercellular substance soluble in hyaluronidase). The fat-mobilization and exophthalmos occur in thyroidectomized animals. These effects are prevented if TTH is given simultaneously with thyroxine. The protective effect of thyroxine is not due to its ability to elevate the BMR, since dinitrophenol and sulfur precipitate in oil both failed to protect against fat mobilization and exophthalmic effects of TTH, although these agents did elevate the BMR. The authors believe that this indicates a specific antagonism between TTH and thyroxine at the level of the peripheral cells.