Abstract
Pituitary growths induced by thyroid destructive doses of I131 are readily transplantable in mice whose thyroid glands had been similarly destroyed, but not in normal mice. These growths discharge gonadotropic hormones which in turn stimulate the production of gonadal hormones. Discharge of thyrotropic hormones by these tumors is assumed but remains to be demonstrated. On the basis of observations made it is postulated that: a) The growths of the pituitary induced by thyroid-destroying quantities of I131 are conditioned neoplasms formed by cells which are driven to proliferation through the stimulus created by the absence of TH; b) The same chromophobe pituitary cell can discharge both gonadotropic and thyrotropic hormones.