Metabolism of [3-14C] coumarin by human liver microsomes

M. L. P. S. van Iersel, C. J. Henderson, D. G. Walters, R. J. Price, C. R. Wolf, B. G. Lake

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    Abstract

    1. The metabolism of 50 mu M [3-C-14] coumarin has been studied in a panel of 12 human liver microsomal samples of known P450 isoenzyme profile.

    2. [3-C-14] coumarin was metabolized by human liver microsomes to various polar products including 3-, 4- and 7-hydroxycoumarins (3-HC, 4-HC and 7-HC) 6,7-dihydroxycoumarin (6,7-DiHC), o-coumaric acid (o-CA), o-hydroxyphenyl-acetaldehyde (o-HPA), o-hydroxyphenylethanol (o-HPE), o-hydroxyphenylacetic acid (o-HPAA) and o-hydroxyphenylpropionic acid (o-HPPA) and to product(s) that bind covalently to microsomal proteins.

    3. For all 12 subjects, mean rates of [3-C-14] coumarin metabolism to total polar products (metabolism to all products except product(s) covalently bound to microsomal proteins), 7-HC, the 3-hydroxylation pathway (sum of 3-HC, o-HPA, o-HPE and o-HPAA), o-HPPA, 6,7-DiHC and covalent binding were 1420, 1230, 73.8, 52.5, 9.5 and 4.8 pmol/min/mg protein respectively.

    4. Marked interindividual differences in [3-C-14] coumarin metabolism to total polar products (30-fold variation) and 7-HC (2250-fold variation) were observed.

    5. Good correlations were observed between [3-C-14] coumarin metabolism and total polar products, 7-HC, o-HPPA and 6,7-DiHC, but not to 3-hydroxylation pathway products and levels of 2A6 and 2B6 in human liver microsomes.

    6. [3-C-14] coumarin metabolism to any polar products did not correlate with levels of 1A2, 2C8, 2C9, 2E1, 3A3/4 and 4A1 in human liver microsomes.

    Original languageEnglish
    Pages (from-to)795-803
    Number of pages9
    JournalXenobiotica
    Volume24
    Issue number8
    DOIs
    Publication statusPublished - Aug 1994

    Cite this

    van Iersel, M. L. P. S., Henderson, C. J., Walters, D. G., Price, R. J., Wolf, C. R., & Lake, B. G. (1994). Metabolism of [3-14C] coumarin by human liver microsomes. Xenobiotica, 24(8), 795-803. https://doi.org/10.3109/00498259409043279