CHARACTERIZATION OF THE LONG-ACTING THYROID STIMULATOR OF GRAVES' DISEASE

Abstract

A method for the isolation of the long-acting thyroid stimulator (LATS) has been described which identifies the activity with the 7S gamma globulin proteins. Activity is retained in a single fraction when the protein is subjected to chemical reduction or to enzymatic digestion; however, the bioassay response shows the poly-peptide subunits to be short-acting and to resemble thyrotropin. Thus the prolonged thyroid stimulation which is characteristic of LATS is dependent upon the intact gamma globulin protein. Because of the well-recognized function of the 7S gamma globulins to serve as antibody, it appears that the long-acting thyroid stimulator may in some manner be associated with a specific antigen-antibody response.