THE BINDING CAPACITY OF ALBUMIN AND RENAL DISEASE

¹ Department of Medicine, University of Auckland, School of Medicine, Auckland, New Zealand

The capacity of albumin to bind the anionic dye, methyl orange (4'-dimethylaminoazobenzene-4-sulfonate), was determined in normal volunteers, in patients with renal disease and in patients after kidney transplantation in an attempt to elucidate the cause of the observed decreased albumin binding capacity for various drug and dye molecules in these patients. Patients with renal failure had lower binding capacities than normal volunteers and this reduction was generally unrelated to the degree of renal failure. The order of binding capacity was: normals > patients with acute and chronic renal failure > anephric patients before hemodialysis > patients after kidney transplantation > anephric patients after hemodialysis. The reduced binding after dialysis was shown to be caused by competition by the temporarily increased concentration of nonesterified fatty acids as a result of lipoproteinlipase activation by heparin administered during hemodialysis. The cause of the decreased binding of the other sera was not apparent but may have been due to either drug and/or metabolic product competition for the dye binding sites on due to a conformational change in the albumin molecule.