THE EFFECTS OF THYROIDECTOMY AND THYROID‐FEEDING UPON THE ADRENALIN CONTENT OF THE SUPRARENALS

Complete thyroidectomy has little, if any, permanent effect upon the adrenalin content of the suprarenals of the rabbit—an animal in which no characteristic symptoms follow removal of the thyroids. In cats the adrenalin content of the suprarenals is diminished in direct proportion to the severity of the symptoms induced by removal of the thyroids. The amount of adrenalin in the suprarenals is found to be up to the average normal amount in cats which show no symptoms. In those cats which exhibit tetany, progressive muscular weakness, and emaciation subsequent to removal of the thyroids and parathyroids, the adrenalin is greatly reduced, and the greater the muscular weakness the greater is found to be the loss of adrenalin. The absence of symptoms following upon complete removal of the thyroids and parathyroids is not infrequent in cats, and has been noted in the Macacus rhesus monkey. The adrenalin content of the suprarenals per kilogramme body-weight is higher in rabbits than in cats, the figures averaging 0·400 mg. and 0·229 mg. respectively for the normal animals examined. In cats which receive large amounts of raw ox thyroid in addition to their ordinary diet, the amount of adrenalin in the suprarenals is increased, the amount averaging 0·347 mg. per kilogramme body-weight in the thyroidfed cats examined against 0·229 mg. in the normal. The relative amounts of adrenalin in the suprarenals of normal, thyroidectomised, and thyroid-fed animals have been ascertained by physiological methods and by Folin' s colorimetric method. The results are in agreement.