Improved assay of urinary total 17-hydroxycorticosteroids

A reliable method for the quantitative determination of "total 17-hydroxycorticosteroids has been described. Urine is subjected to reduction with sodium borohydride which reduces the 17-hydroxy-20-keto-21-deoxy steroids to 17,20-dihydroxy-21-deoxy steroids and 17-ketosteroids to C19 17-hydroxysteroids. Subsequent oxidation with sodium bismuthate oxidizes all the C21 17-hydroxysteroids to the corresponding 17-ketosteroids, which are extracted with CHCl3 : Bu-OH using ammonium sulfate as the salting out agent and finally the color reaction is performed with m-dinitrobenzene and the absorbance is measured. The 17-ketosteroids originally present in the urine do not interfere, since NaBH4 reduces them to C19 17-hydroxysteroids which cannot be oxidized with sodium bismuthate and do not respond to the color reaction with m-dinitrobenzene.