The effect of thyreotropic hormone and of desiccated thyroid upon creatine and creatinine excretion

Abstract

The feeding of 2 grains of desiccated thyroid per day to normal rats caused a rise in the creatine excretion which reached a peak on the 10th day and then gradually decreased while the metabolic rate was still rising. Intraperit. injections of the thyreotropic hormone of the anterior pituitary caused a temporary increase in creatine excretion, both in normal and hypophysectomized rats, but had no effect on the creatinine excretion. A significant increase in the creatine excretion was obtained with 6 units of the thyreotropic hormone in the normal rat and with 1 unit in the hypophysectomized rat. Purified extracts of the growth hormone, and of the adrenotropic hormone had no effect on the creatine or creatinine excretion of normal rats. Thyreotropic hormone inactivated by boiling also gave negative results. Anti-thyreotropic substance, which inhibited the rise in metabolic rate by thyreotropic hormone, did not prevent an increase in creatine excretion.