THE METABOLISM OF NORMAL PLASMA PROTEINS AND GAMMA-MYELOMA PROTEIN IN MICE BEARING PLASMA-CELL TUMORS

Abstract

The metabolism of normal mouse gamma-globulin, of a mouse gamma-myeloma protein, of normal human gamma-globulin, and of mouse albumin was studied using purified proteins labelled with I131. These proteins were studied in normal C3H mice and in mice bearing a gamma-type plasma cell tumor, a beta-2A type plasma cell tumor, or a mammary carcinoma with similar growth characteristics. In normal mice the half time for the turnover of all 3 gamma globulins was 4.6 days, while the half time for albumin was 1.54 days. Gamma myeloma globulin behaved as normal gamma globulin. The gamma plasma cell tumor caused a marked acceleration of gamma globulin catabolism, while the beta-2A tumor had much less effect and the mammary carcinoma had no such effect. Normal C3H mice synthesized about 20 X more albumin than gamma globulin each day. In a plasma cell tumor, however, the rate of gamma myeloma protein synthesis was approximately the same as the rate of albumin synthesis in the liver.