Abstract
This laboratory previously reported a radioimmunoassay (RIA) for aldosterone based on prior purification by solvent partitioning, periodate oxidation and a single thin-layer chromatogram. Other methods reported to date require paper chromatography to attain the required specificity. The method presented herein utilizes antibodies produced to aldosterone-γ-lactone 3-carboxymethyl oxime coupled to BSA. Aldosterone-γ-lactone constitutes the ligand. Overall interference is: cortisol 0.07%, corticosterone 0.02%, progesterone 0.17%, estradiol-ND, testosterone 0.02%, and 18-hydroxy corticosterone 0.29%. The purification procedure consists of CHCI3 extraction, benzene:H2O partition, periodate oxidation and bicarbonate wash. Recovery is determined from added 3H- or 14Caldosterone and is 40–50%. Simultaneous GC and RIA of urine samples (μg/24 hr) are:
The correlation between GC and RIA methods is 0.95% (p < .01). RIA values with and without TLC showed no significant difference. This method is simple and reproducible. It can be accomplished in less than one working day without sacrificing specificity. This method can be utilized in the clinical laboratory.
