Non-Specificity of Thyrotropic Antihormone.∗

Summary Daily injections of Jieep-pituitary extract into a dog produced an antihormone which inactivated in guinea pigs substantial test doses of thyrotropic hormone from sheep and bovine pituitary glands and f rom human urine oi myxoedenia. Injections of the serum alone into guinea pigs produced upon their thyroids an effect which resenibled hypophysectomy.