Serum Concentration of Prednisolone in Children with Nephrotic Syndrome

Abstract

[Purpose] Recently prednisolone has been used clinically for the therapy in children with nephrotic syndrome. But little information was available about the study of the absorption and excretion of prednisolone in the nephrotic syndrome. So we invented new easy radioimmunoassay (RIA) for prednisolone, and measured the serum concentration of prednisolone in children with nephrotic syndrome. [Methods] Three rabbits were injected with prednisolone 21-BSA hapten and Freund's adjuvant. The rabbit serum(anti-prednisolone antibody) and goat anti-rabbit gamma globulin was used for RIA by double antibody technique. By heating unknown serum in 70°C for 30 minutes, the native prednisolone binding protein was denatured, and it was possible to analyze prednisolone in unextracted and nondiluted serum. Twenty children with idiopathic nephrotic syndrome were administered orally prednisolone several times. The quantity of prednisolone was equal in the each patient. The serum concentration of prednisolone was measured serially. [Results and Discussion] This RIA was capable of detecting 50 picograms of prednisolone in 50 μ1 of undiluted serum. The peak concentration of prednisolone in patients had a tendency to increase gradually with the decrease of the urine protein. The tendency had little correlation with the change of the total protein in serum.