The Relation Between Free Cortisol in Urine and 'Urinary Free 11-Hydroxycorticosteroids' as Measured by Fluorescence

Abstract

The relation between free cortisol in urine and 'free \g=D\4\m=.\3keto-11\x=req-\ 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\m=.\96), the percentage contribution to the free 11\ x=r eq-\ hydroxycorticosteroids made by true cortisol was small (mean 33 %) and varied from 8 to 73 % in different urine samples.