METABOLISM OF ETHYNYLOESTRADIOL IN MAN

in Journal of Endocrinology
Authors:
M. J. REED
Search for other papers by M. J. REED in
Current site
Google Scholar
PubMed
Close
,
K. FOTHERBY
Search for other papers by K. FOTHERBY in
Current site
Google Scholar
PubMed
Close
, and
S. J. STEELE
Search for other papers by S. J. STEELE in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

SUMMARY

The metabolism of 17α-ethynyloestradiol was studied in one man and 16 women. After intravenous or oral administration, 22·6–46·9% of the dose was excreted in the urine over a 5-day period. Up to 36% of the urinary radioactivity may be present in the unconjugated form with a further 64% being extractable after enzymic hydrolysis. Sulphate conjugates formed only 11·4% of the urinary radioactivity. Semi-quantitation of these extracts showed ethynyloestradiol itself to be the major metabolite, accounting for 3·2–8·4% of the administered dose in the unconjugated fraction with a further 2·4–16·5% in the enzyme hydrolysed fraction. Up to 16·5% of the dose was therefore excreted unchanged, and metabolites less and more polar than ethynyloestradiol were also found. Excretion via the faeces accounted for up to 30% of the administered dose, with most of the extractable radioactivity being in the unconjugated form. Ethynyloestradiol accounted for up to 29·6% of faecal radioactivity. No significant amounts of radioactivity were detected in sweat collected from one subject 2 or 24 h after administration of the dose. Plasma levels of 3·32% and 1·72% of the administered dose per litre were found 1 and 24 h after administration. Metabolites in plasma were present mainly as sulphate conjugates.

 

  • Collapse
  • Expand