Stuart W. Lippincott

DETERMINATION OF RADIOACTIVELY LABELED GLOBULIN TURNOVER BY THE DIRECT WHOLE-BODY COUNTING TECHNIQUE

The turnover rates of I131 labeled beta and gamma globulins in a hypergammaglobulinemic multiple myeloma patient were compared by the conventional serum and urinary excretion methods with those found using the in vivo whole-body gamma spectrometer counting method. The fractionated radioactively labeled globulins used in these studies were considered by free (Tiselius) electrophoresis and ultracentrifugal patterns to have an acceptable degree of homogeneity. The half-life for the beta globulin was 9.9 days by the serum concentration method, 8.7 days by the urinary excretion method, and in two different studies by the in vivo whole-body counter method, 10.3 and 9.8 days, respectively. The half-life for the gamma globulin utilizing urinary data was 6.5 days as compared to 6.3 days for the whole-body counter method. Finally, by the latter technique, with a different gamma globulin preparation, the half-life was 7.1 days.