THE EFFECTS OF PITUITARY AND NON-PITUITARY GLAND FACTORS ON THE FORMATION OF INTRACELLULAR COLLOID DROPLETS IN THE THYROID EPITHELIUM OF HYPOPHYSECTOMIZED RATS1

Abstract

In hypophysectomized rats administration of small doses of pituitary extract resulted in appearance of thyroid colloid droplets. More droplets followed larger dosage. Thy-roxine or iodide given simultaneously did not prevent this response. As the time interval between hypophysectomy and a fixed dosage of pituitary extract admn. was increased, there was a progressive decrease in droplet number. Droplets in normal rat thyroids exposed to cold or thiouracil disappeared with hypophysectomy. In normal rats exposed to cold or fed thiouracil with thyroxine, droplet formation was inhibited. Under other conditions droplet formation was independent of thyroxine.