INVESTIGATIONS ON THE ESTIMATION OF 17-HYDROXYCORTICOIDS IN URINE USING THE PORTER/SILBER REACTION

Abstract

The phenylhydrazine reaction was applied to 3 types of urinary extracts: 1 extracted with CHCl3 at pH 1 followed by Girard separation; a 2d after hydrolysis at pH 5 with 300 Fishman Units of beta-glucuronidase at 37[degree] C for 72 hrs.; and a 3d combining both methods. Urine extracted at pH 1 yields Porter-Silber (P-S) reacting material equivalent to approx. 90 [mu]g/ 24 hrs., a value similar to that obtained by bioassay. The excretion increases after surgery or ACTH and is low in Addison''s disease or hypopituitarism. Glucuronidase-released P-S reacting material ranges from 1-8 mg./24 hrs., and increases after admn. of cortisone or insulin. The combined method gives vlaues 10-15% higher than the glucuronidase method. The technique can be performed on 2 ml. of urine and is suitable to mass analytical techniques.