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The gut wall metabolism of ethinyloestradiol and its contribution to the pre‐systemic metabolism of ethinyloestradiol in humans.
Author(s) -
Back DJ,
Breckenridge AM,
MacIver M,
Orme M,
Purba HS,
Rowe PH,
Taylor I
Publication year - 1982
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1982.tb01382.x
Subject(s) - metabolism , first pass effect , portal vein , vein , medicine , peripheral , endocrinology , pharmacology
1 Five patients have been studied to determine the contribution of the gut wall to the pre‐systemic metabolism of ethinyloestradiol. All patients had a catheter inserted into their hepatic portal vein as part of their surgical management. 2 After an oral dose of 50 micrograms (65 microCi) ethinyloestradiol, blood samples were taken from the hepatic portal vein and from a peripheral vein at intervals for 1 h. 3 In each patient the concentration of conjugated ethinyloestradiol in the portal vein was considerably higher than in the peripheral vein. 4 Although a number of assumptions have been made, calculations showed that the gut wall appeared to be twice as effective as the liver in conjugating ethinyloestradiol on the first pass. 5 In two patients there was no evidence of major uptake or metabolism of ethinyloestradiol in the lung.