THE EFFECT OF ADRENAL AND PITUITARY HORMONES ON THE URINARY EXCRETION OF IODIDE IN MICE1

The urinary excretion of radioiodide was measured in mice injected with a variety of adrenal and pituitary hormones. While radioiodine excretion was diminished in adrenalectomized mice and restored to a nearly normal rate by cortisone, this hormone, as well as aldo-sterone, deoxycorticosterone, adrenaline and noradrenaline, had little effect in intact mice. ACTH was slightly ioduretic and TSH had no effect. A considerable increase in radioiodide excretion was observed after acute injection of the posterior pituitary hormones, vasopressin and oxytocin. The effect of vasopressin did not depend on the amount of impurity present in the preparations tested, and varied linearly with the logarithm of the dose. This hormone increased the renal clearance of radioiodide from blood. These ob-servations suggest that the posterior pituitary plays a role in the control of iodide excretion. When vasopressin was administered for prolonged periods of time, the resulting iodide losses, unlike those produced by sodium chloride administration, did not induce a stimulation of the thyroid gland. In fact, vasopressin depressed the thyroid gland since the thyroid weight was reduced to about 40% of that in controls. Presumably, this effect prevented the iodine losses from resulting in thyroid stimulation.