Abstract
Although there are numerous studies of glucuronidation of endogenous compounds, information on the glucuronidation of fatty acids is lacking. In the present studies, both linoleic acid (LA) and its biologically active oxidized derivatives, 13-hydroxyoctadecadienoic acid (13-HODE) and 13-oxooctadecadienoic acid (13-OXO), have been shown to be effective substrates for human liver UDP-glucuronosyltransferases (UGT) and recombinant UGT2B7. LA (carboxyl glucuronide) and 13-OXO (carboxyl glucuronide, unproven) were actively glucuronidated by human liver microsomes (HLM) and human recombinant UGT2B7 with similar activities, in the range of 2 nmol/mg · min. The hydroxyl derivative of LA, 13-HODE, was glucuronidated at both the hydroxyl and carboxyl functions with carboxyl glucuronidation predominating (ratio of COOH/OH, 2:1). For all substrates, the Kmfor formation of the carboxyl-linked glucuronide was in the range of 100 to 200 μM while that for the hydroxyl-linked glucuronide was somewhat lower (>100 μM). This is the first demonstration of glucuronidation of LA and its oxidized derivatives, 13-HODE and 13-OXO, by HLM and recombinant UGT2B7.
Footnotes
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Send reprint requests to: Anna Radominska-Pandya, Department of Biochemistry and Biophysics, University of Arkansas for Medical Sciences, 4301 W. Markham St., Slot 516, Little Rock, AR 72205. E-mail: RadominskaAnna{at}exchange.uams.edu
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This research was supported in part by National Institutes of Health Grants DK56226 and DK49715 (to A.R.-P.) and CA76420 (to A.W.B.).
- Abbreviations used are::
- LA
- linoleic acid
- 13-HODE
- 13-hydroxyoctadecadienoic acid
- 13-OXO
- 13-oxooctadecadienoic acid
- UGT
- UDP-glucuronosyltransferase
- UDPGlcUA
- UDP-glucuronic acid
- 13-HPODE
- 13-hydroperoxyoctadecadienoic acid
- z
- cis
- e
- trans
- HLM
- human liver microsomes
- TLC
- thin-layer chromatography
- HPLC
- high-performance liquid chromatography
- FAB
- fast atom bombardment
- Rf
- retardation factor
- Received July 7, 2000.
- Accepted January 2, 2001.
- The American Society for Pharmacology and Experimental Therapeutics
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