Abstract
The weight of the thyroidal gland increased by the use of methylthiouracil and was inhibited by chlorpromazine in experimental animals. The administration of MTU provoked not only an enlargement of the thyroid gland, but also an elevation of neurosecretion of the hypothalamic neurosecretory system. Thyroidectomy produced the most remarkable changes of the hypothalamic neurosecretory system. Chlorpromazine inhibited the hypothalamic neurosecretion and depressed the release of pituitary thyrotrophin. Thus the effect of methylthiouracil, chlorpromazine, and potassium iodide on the thyroid gland appears to be mediated through the hypothalamic neurosecretory system.
