Persistent endocrine therapy often leads to the development of hormone refractoriness. A continuation of the therapy after this condition develops is of little value and may cause deleterious results. Collip1 and his co-workers showed that hormone refractoriness may develop in experimental animals even though endocrine products from the same animal species are selected and that acquired hormone refractoriness is serologically transferable. Determination of the origin, nature and method of action of the serum component responsible for this transfer is of basic clinical interest.
The refractoriness serum components have been considered to be inhibiting hormones or hormonedestroying enzymes presumably formed as a result of a compensatory hypertrophy of antagonistic endocrine glands. This theory finds some histologic support2 and is apparently confirmed by the indirect serologic evidence recently reported by Sulman,3 of the Rothschild Hospital, Jerusalem.
Sulman tested the antigenic properties of a wide range of gonadotropic substances in