RADIOIMMUNOASSAYS OF TETRAHYDROCORTISONE AND TETRAHYDROCORTISOL IN HUMAN URINE

Abstract

ABSTRACT A simple radioimmunoassay for the determination of tetrahydrocortisone (THE)1), and tetrahydrocortisol (THF) as well as their 21-glucosiduronate conjugates is described. White New Zealand rabbits were immunized with THF- and THE-20-oxime-bovine serum-albumin conjugates. The resulting antisera proved to be very specific. Both allo-THE and allo-THF gave minimal cross-reactions; however, THE- and THF-21-glucosiduronate bind with the corresponding antibodies at a level of 100 %. The following types of estimations were introduced: a) Estimation of the sum of unconjugated THF and THF-21-glucosiduronate in highly diluted unprocessed human urine. b) A similar estimation of THE and THF-21-glucosiduronate as in a). c) Estimation of THF after β-glucuronidase treatment and dilution without further procedures. d) A similar estimation for THE as in c). THF and THE values correlate significantly with known parameters that characterize the cortisol production, such as cortisol secretion rate and the urinary corticoid (C21-α-ketolic-steroid) levels.