STUDIES ON A THYROID STIMULATING FACTOR IN URINARY CHORIONIC GONADOTROPHIN PREPARATIONS

Abstract

Thyroid stimulating activity was demonstrated in human urinary chorionic gonadotropin preparations (HCG) by the method of McKenzie (1958). The biological response of the material was similar to that of bovine pituitary thyrotropin (TSH), but no neutralization of the activity occurred with antibodies against human pituitary TSH and, even more interesting, with antibodies against human urinary chorionic gonadotropin preparations. The latter antibodies perfectly neutralized human pituitary TSH. The Gamma-G-globulins precipitated from a mixture of HCG and anti-HCG contained biological activity whereas no activity was recovered in the Gamma-G-globulin fraction when HCG was mixed with non-immune rabbit serum. This may indicate the presence of a soluble antigen-antibody complex.