POLY-MALEIC ACID ANHYDRIDE (PMA) COUPLED CORTISOL ANTIBODY IN ROUTINE DETERMINATION OF URINARY FREE CORTISOL

Abstract

ABSTRACT Antibodies against cortisol-21-hemisuccinate conjugated to bovine serum albumin was raised in rabbits and conjugated with poly-maleic acid anhydride. The conjugate was used in a solid phase radioimmunoassay to measure the urinary excretion of unconjugated cortisol. Cortisol was extracted with methylene chloride, the extract purified by chromatography on Sephadex LH-20, and the cortisol content measured with the radioimmunoassay. The intra-assay variation of the method was 6 per cent and the interassay variation 10 per cent. In 95 normal adult persons the excretion of free cortisol was 11–70, mean 30 μg/24 h. No sex or age difference was found. In 8 children aged 7–14 years the excretion was 8–46 μg/24 h.