Two series of chemical compounds have been found to possess the unique property of inhibiting the endocrine function of the thyroid gland. The administration of these agents to experimental animals is followed, after a short latent period, by a lowering of the basal oxygen consumption, a decrease in the rate of growth and development and a diminished food intake—changes which are consistent with a state of hypothyroidism. In certain animal species these changes are accompanied by a hyperplasia of the thyroid gland which is apparently compensatory in nature and mediated by the anterior lobe of the pituitary. It was the object of this investigation to determine whether the endocrine function of the human thyroid gland could be inhibited by these compounds and to obtain information concerning their dosage and toxicity in individuals with normal thyroid glands and in cases of hyperthyroidism.
It was first pointed out by the Mackenzies and