Studies of Phenolic Steroids in Human Subjects. XIX. Renal Conjugation of 15α-Hydroxyestradiol-3-sulfate

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Abstract
In order to elucidate further the role of the kidney in the conjugation and excretion of 15α-hydroxy-estrogens, we synthesized doubly and singly labeled 15α-hydroxyestradiol-3-sulfate (15α-OHE2-S) and determined its urinary excretoiy pattern after administering differently labeled 15α-OHE2-S into the renal artery and coneomitantly into a peripheral vein and by the infusion of doubly labeled 3H-15α-OHE2-S−35S into the renal artery-The excretion of radioactivity in the early urinary samples and the conjugate pattern in these urines were determined. About twice as much radioactivity was excreted in the early urine samples originating from the renal artery injection than from samples obtained following peripheral administration, indicating renal conjugation and excretion of the 15α-OHE2-S. The latter was preponderantly excreted as the S-NAG with only a small part (about 10%) of the administered sulfate being hydrolyzed to the aglycone. The latter was then either conjugated with N-acetylglucosamine (NAG) or glucuronide, probably also in the kidney. Most of the 15α-OHE2-S could not be accounted for, possibly because of biliary excretion and enterohepatic circulation. The results obtained and those already published indicate that the human kidney is capable of conjugating 15α-OHE2, its NAG, and its sulfate conjugates.