The use of deuterium-labeled cortisol for in vivo evaluation of renal 11 beta-HSD activity in man: urinary excretion of cortisol, cortisone and theirA-ring reduced metabolites

This study describes a new approach using stable isotope methodology in eva luating 11 beta-HSD activities in vivo based on urinary excretion of cortis ol, cortisone, and their A-ring reduced metabolites. The method involved th e measurement of deuterium-labeled cortisol and its deuterium-labeled metab olites by GC/MS simultaneously with endogenous cortisol, cortisone, and the ir A-ring reduced metabolites after oral administration of deuterium-labele d cortisol to normal human subjects. This stable isotope approach offered u nique advantages in assessing the appropriateness of measuring unconjugated and total (unconjugated + conjugated) cortisol, cortisone, and their A-rin g reduced metabolites in urine as indices of renal 11 beta-HSD2 activity in man. Our results strongly support that the measurement of urinary unconjug ated cortisol and cortisone is a significant advance in assessing 11 beta-H SD2 activity. (C) 2000 Elsevier Science Inc. All rights reserved.