Studies on phenolic steroids in human subjects: IX. Role of the intestine in the conjugation of estriol

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Abstract

In order to compare the enteric circulation of estriol-16α-glucosiduronate (see preceding paper) with that of estriol (E3), labeled estriol was administered to six women by several routes: both injection and infusion (300 min) into the cubital vein, injection into the portal vein system, ingestion and instillation into the jejunum and ileum. Urine, collected from 0-2, 2-4, 4-8, 8-12, and 12-24 hr, was analyzed by countercurrent distribution for its content of radioactive 3- and 16-glucosiduronate (E3-3Gl,E3-16Gl) and sulfoglucosiduronate (E3-3S,16Gl) of estriol. After peripheral injection of E3, E3-16Gl was excreted rapidly and E3-3S,16Gl at a slower and more constant rate. E3-3Gl was barely detectable after infusion. After injection of E3 into the portal vein, the excretion of E3-3S,16Gl was greater and quicker than after peripheral injection. Even in a subject with a complete bile fistula, the urinary excretion of E3-3S,16Gl was essentially unchanged. Ingestion also produced the same result. Only after instillation into the ileum was a large and rapid excretion of E3-3Gl obtained, whereas the excretion of E3-3S,16Gl, and E3-16Gl were depressed. These results together with those of the preceding paper suggest that E3 does not readily appear in the small intestine except via a hepatoenteric circulation that produces very little E3-3Gl. When present in the distal segment of the small intestine, however, absorption, conjugation, and elimination proceed readily.

Authors

N. Inoue, A. A. Sandberg, J. B. Graham, W. R. Slaunwhite Jr.