Thyrotropic and “Long-Acting Thyroid Stimulator” Effects from Certain Polypeptides1

Abstract

Bio-assay responses resembling those elicited by “long-acting thyroid stimulator” (LATS) of Graves' disease have been obtained in the thyroxine-suppressed mouse with alpha MSH, human MSH, arginine and lysine vasopressins, and serotonin. Responses like those from TSH were given by beta MSH and ACTH administered in saline, but became like that of LATS when the materials were injected in normal human serum. The synthetic and natural oxytocins were inactive. The kinin, bradykinin, also was inert, but its decapeptide derivative, kalhdin, produced an LATS-type of response. Anterior pituitary hormones contaminated with TSH gave a typical TSH-type response both in saline and in human serum; those not containing TSH gave no assay response.