[A comparative study of the kinetics of 131I-bromsulphthalein and 125 I-biligrafin (author's transl)].

The kinetics of 131I-Bromsulphthalein (BSP) and 125I-Biligrafin were compared with one another. 131I-BSP is taken by the liver ten times faster than 125I-Biligrafin. The distribution volumes of these two tracers are identical. The maximum transport capacities (Tm) of BSP and Biligrafin are inversely proportional to the elimination constant k of the blood. The Tm of BSP is 8.6 +/- 1.9 mg/min., of biligrafin is 35.8 2.2 mg/min. Biligrafin leaves the liver cells without prior metabolization, which could account the higher Tm of this preparation. In conformity with theoretical considerations, 131I-BSP and 125I-Biligrafin differ in the following important respects: 131-I-BSP leads to a high activity in the liver against a low background activity. With labelled Biligrafin, on the other hand, on account of the slow activity in the liver and the high Tm, a striking contrast is demonstrable between liver and bile duct. This could, perhaps, be of diagnostic value in localizing a bile fistula.