THE RELATION BETWEEN FREE CORTISOL IN URINE AND 'URINARY FREE 11-HYDROXYCORTICOSTEROIDS' AS MEASURED BY FLUORESCENCE

Abstract

SUMMARY: The relation between free cortisol in urine and 'free Δ4·3 keto-11-hydroxycorticosteroids' has been explored by measurements in sixty urine samples. Free cortisol was measured by a method which involved paper chromatography and incorporated an internal isotopic standard to correct for losses. A rapid and simple technique, measuring fluorescence in ethanolic sulphuric acid, was used to determine the free 11-hydroxycorticosteroids. Although there was a good correlation between the two measurements (r = 0·96), the percentage contribution to the free 11-hydroxycorticosteroids made by true cortisol was small (mean 33 %) and varied from 8 to 73 % in different urine samples.