Evidence from rat hepatocytes of an unrecognized pathway of 5-fluorouracil metabolism with the formation of a glucuronide derivative

J. P. Sommadossi, D. S. Cross, D. A. Gewirtz, I. David Goldman, J. P. Cano, R. B. Diasio

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Isolated rat hepatocytes in suspension were exposed to [3H]5-fluorouracil for intervals over 2 h, following which the cells were removed from the media and sonicated, and the cytoplasm was sampled. High-performance liquid chromatography was used to separate 5-fluorouracil (FUra) from its known anabolites and catabolites, with subsequent quantitation of these metabolites by measurement of radioactivity. As the extracellular concentration of FUra was increased above 30 μM, the intracellular levels of FUra increased, with detection of a new peak of radioactivity distinct from any of the known anabolites or catabolites. This new metabolite, 'G', increased in concentration as the extracellular concentration of FUra was raised above 1 mM. Inhibition of FUra catabolism by 2 mM thymine resulted in a further increase in intracellular FUra (approaching the extracellular FUra concentration) and was accompanied by a further increase in the intracellular concentration of 'G', demonstrating that 'G' was not formed via the catabolic pathway. The increase in intracellular FUra and 'G' was not accompanied by an increase in intracellular anabolites, suggesting that 'G' was formed via a novel metabolic pathway. 'G' was retained within the hepatocytes, although it was not bound to intracellular macromolecules. 'G' was converted to FUra in the presence of β-D-glucuronidase; this reaction was inhibited with the addition of saccharo-1,4-β-lactone, a specific inhibitor of the β-D-glucuronidase. This data, together with evidence from hepatocyte homogenates in which formation of 'G' was shown to be dependent on the concentration of uridine-5'-diphosphoglucuronic acid, demonstrates that 'G' is a glucuronide of FUra. The formation of 'G' suggests that FUra is metabolized via a previously unrecognized metabolic pathway.

Original languageEnglish (US)
Pages (from-to)2450-2455
Number of pages6
JournalCancer Research
Volume45
Issue number6
StatePublished - 1985
Externally publishedYes

Fingerprint

Glucuronides
Fluorouracil
Hepatocytes
Glucuronidase
Metabolic Networks and Pathways
Radioactivity
Uridine Diphosphate Glucuronic Acid
Thymine
Lactones
Suspensions
Cytoplasm
High Pressure Liquid Chromatography

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Evidence from rat hepatocytes of an unrecognized pathway of 5-fluorouracil metabolism with the formation of a glucuronide derivative. / Sommadossi, J. P.; Cross, D. S.; Gewirtz, D. A.; Goldman, I. David; Cano, J. P.; Diasio, R. B.

In: Cancer Research, Vol. 45, No. 6, 1985, p. 2450-2455.

Research output: Contribution to journalArticle

Sommadossi, J. P. ; Cross, D. S. ; Gewirtz, D. A. ; Goldman, I. David ; Cano, J. P. ; Diasio, R. B. / Evidence from rat hepatocytes of an unrecognized pathway of 5-fluorouracil metabolism with the formation of a glucuronide derivative. In: Cancer Research. 1985 ; Vol. 45, No. 6. pp. 2450-2455.
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AU - Diasio, R. B.

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