A marked increase of the serum beta globulins was found in rabbits developing amyloidosis as a result of prolonged treatment with ribonucleate administered by subcutaneous injections. Following cessation of treatment the beta globulin levels gradually returned to normal while the gamma globulin levels rose strikingly, the changes being accompanied by a resorption of amyloid from the spleen, and probably also from the kidneys. Electrophoretic studies provided some evidence that the increase in beta globulins which accompanied the development of amyloidosis resulted from the production of a globulin not normally present in rabbit serum. A protein or protein derivative that moved as a beta globulin when subjected to filter paper electrophoresis was excreted in substantial quantities in the urine of several amyloidotic rabbits, along with much smaller quantities of substances moving as albumin, alpha and gamma globulins.
Considered as a whole, the findings indicate a causal relationship between the abnormal production of circulating beta globulins and the deposition of amyloid in rabbits treated with ribonucleate. Hence it appears that a beta globulin may be directly involved in the formation of amyloid under the conditions of the experiments here reported.