Effect of Tritium Labeling of Cortisol on Its Physical-Chemical Properties and on Its Metabolism in Man

Abstract

The separation of tritium-labeled from nonlabeled or C14-labeled steroids on paper partition chromatograms has been described and its implications have been discussed. In addition, cortisol-1,2-H3 and cortisol-4-C14 were administered simultaneously to a normal man, and labeled steroids from urine and plasma, collected at intervals during the first 24 hr., were isolated by paper chromatographic procedures. All metabolites exhibited chromatographic separation of the H3-containing moiety from the nonlabeled or C14-labeled compounds. However, no isotope effect was discernible for the in vivo metabolism of cortisol-1,2-H3. When care was taken to analyze the total chromatographic peak areas, the proportions of H3:C14 in the isolated metabolites (cortisol, cortisone, 3[alpha], 11[beta], [beta]7, 21-tetrahydroxy-5[beta]-pregnan-20-one, 3[alpha],11[beta],17,21-tetrahydroxy-5[alpha]-pregnan-20-one, 3[alpha],17,21-trihydroxy-5[beta]-pregnane-11,20-dione)and a mixture of the cortolones were identical with that in the administered steroids.