THE DETERMINATION OF URINARY 17-TRIOXYSTEROIDS* BY RAYMOND RIVOIRE,t

The color reaction characteristic of cortisone and related compounds (with the 17,21-dihydroxy-20-keto grouping), which Porter and Silber (1) reported in 1950, has been used by a number of investigators to measure the “cortisone-like” metabolites of urine. To facilitate expression, we propose to give to the methods of analysis utilizing this reaction the term of “determination of 17-trioxysteroids;“’ this denomination has a descriptive chemical basis, and it is similar to the one universally utilized to designate the steroids determined by Zimmermann’s reaction; i.e., the determination of 17-ketosteroids. As Kinsella, Baggett, and Glick (2), Schneider (3), Cohen (4), and Venning (5) have shown, it is necessary to incubate the urine with P-glucuronidase to hydrolyze conjugated steroids. The 17-trioxysteroids are eliminated for the most part as glucurono conjugates: without hydrolysis, only the small free fraction, amounting to about one-twentieth of the total, was obtained. Hydrolysis with hydrochloric acid is too drastic for these labile substances, as was demonstrated by Heard, Sobel, and Venning (6). Perhaps it is not so well known that the extraction of corticoids must be carried out with large volumes of solvent, because the partition coefficient between water and chloroform is not very favorable for these compounds, which are slightly soluble in water and not very soluble in chloroform. Baggett, Kinsella, and Doisy (7) have pointed out the difficulty of extraction of all the 17-trioxysteroids with chloroform. Finally, the original Porter and Silber reaction, excellent with pure steroids, is much less satisfactory with extracts of urine, because brown color formation by the reaction with concentrated sulfuric acid obscures the specific yellow color. To obviate this difficulty, the sulfuric acid has