STUDY OF THE CHROMIUM BINDING IN PLASMA OF PATIENTS ON CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

The distribution of chromium (Cr) among the proteins in plasma of three continuous ambulatory peritoneal dialysis (CAPD) patients and in dialysis solutions was studied with 'in vitro' and 'in vivo' Cr-51-labelled plasma. Radiolabelling allows the kinetics of newly added Cr to be investigated. The separation of the proteins was achieved by ion exchange fast protein liquid chromatography, ensuring quantitative recoveries of the Cr-51 activity, transferrin and albumin. In all fractions the proteins were qualitatively characterised by iso electric focusing. The concentrations of transferrin and albumin were determined by nephelometry. The Cr-51 distribution among the plasma proteins was similar for the three patients. The Cr-51 activity was mainly bound to transferrin and, in the beginning of the incubation, in a lesser degree also to albumin. After 1-6 h a shift was observed of the Cr-51 from albumin to an unidentified low molar mass complex (+/- 5000 Da). Two Cr-51 species showed up in the subsequently drained dialysate, but they could not be identified.