A STUDY OF THE COLORIMETRIC DETERMINATION OF URINARY ANDROGENS1 BY A MODIFICATION OF THE OESTING-NEUSTADT METHOD

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Abstract
In the use of a standardized modification of the Oesting-Neustadt method for urinary "androgens," both pure androsterone and various neutral fraction urinary extracts prepared in the usual manner showed increase in color developed on increasing temp. and conc. of alc. However, the results with urinary extracts, referred to androsterone as standard, varied somewhat with different conditions. In these expts., deviations from Beer''s law were indicated with change of conc. of the urinary extracts but not with pure androsterone or (from the work of Saier and Grauer) with dehydroisoandrosterone or mixtures of the two. Such deviations were also indicated in two expts. when Girard''s reagent was used. The existence of such deviations was confirmed by a series of expts. wherein the conc. of the neutral fraction urinary material was varied over a wide range. Use of absolute alc. (in 1 expt.) minimized the deviations; however, use of abs. or 95% alc. entirely is not practical for the Oesting-Neustadt method. Expts. wherein 1:1 dilution with reagent blanks were carried out after color development, yielded results agreeing with those obtained directly from the corresponding conc. (one-half the original). Such findings suggest that the deviations from Beer''s law may be due to interferences and justify our current practice of using small amts. of urinary extract material for detn. Extended preliminary purification, as well as mild hydrolysis methods, may yield material obeying Beer''s law even when water is present in the reaction mixtures, by eliminating the unknown interfering material producing the effect found.