The serum concentrations of unbound, transcortin bound and albumin bound cortisol in patients with dysproteinemia.

Three cortisol fractions, protein-unbound (U-F), transcortin-bound (Tr-F) and albumin-bound cortisol (Al-F) were measured in patients with dysproteinemia by a newly devised isocolloidosmolar equilibrium dialysis method. Total cortisol (Total-F) concentrations in patients with liver cirrhosis (LC), anorexia nervosa (AN) and cachexia due to cancer (CA) were higher than in normal subjects, and those in patients with nephrotic syndrome (NS) and multiple myeloma (MM) remained within the normal range. In all groups of patients, the U-F concentration, which is believed to be the sole active fraction of cortisol, showed significantly higher values than in the normal subjects. We, therefore attempted to find which of the two binding proteins contributes to the elevated U-F concentrations. Concentrations of each cortisol fraction are greatly changed by alterations in the Total-F concentration. We therefore compared the Tr-F against Total-F and Al-F, and U-F against Total-E of patients with those of normal subjects. It was found that decreased transcortin-binding and not albumin-binding in the patients with cirrhosis, nephrotic syndrome and myeloma contributed to an increase in the U-F concentration. Although decreased binding of albumin due to hypoalbuminemia was found in LC, NS, MM, CA and AN, it had relatively little effect on cortisol distribution in the serum.