Dihydropyrimidine dehydrogenase circadian rhythm in mouse liver: comparison between enzyme activity and gene expression
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- 作者：Porsin ; B. ; Formento ; J.-L. ; Filipski ; E. ; Etienne ; M.-C. ; Francoual ; M. ; René ; e ; N. ; Magné ; N. ; et. al.
- 关键词：Circadian rhythm ; Chronopharmacology ; Drug metabolism ; Dihydropyrimidine dehydrogenase
- 刊名：European Journal of Cancer
- 出版年：2003
- 出版时间：April, 2003
- 年：2003
- 卷：39
- 期：6
- 页码：822-828
- 全文大小：203 K
文摘
Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme of 5-fluorouracil (FU) catabolism. The relevance of the measurement of DPD activity for identifying DPD-deficient patients is lessened by circadian variability in DPD activity. Our purpose was to determine whether or not DPD mRNA is sustained by a circadian rhythm. Synchronised mice (male B6D2F1) were sacrificed at 3, 7, 11, 15, 19 or 23 Hours After Light Onset (HALO; eight mice per time-point). Liver DPD activity was determined by a radio-enzymatic assay and liver DPD expression by a reverse transcriptase-polymerase chain reaction (RT-PCR) enzyme-linked immunosorbent assay (ELISA) method. Mice synchronisation was controlled by leucocyte and neutrophil counts. Individual DPD activity ranged from 555 to 1575 pmol/min/mg prot; mean DPD activity was highest at 3 HALO (mean±standard error of the mean (S.E.M.); 1105±70) and lowest at 15 HALO (889±71). Individual liver DPD expression varied from 761 to 3481 units (DPD/β actin ratio); the mean was lowest at 3 HALO (1406±112) and highest at 15 HALO (2067±214). Cosinor analysis indicated that respective double amplitudes of DPD activity and expression were 21 and 30 % of the 24-h mean. The acrophases for activity and expression were 6:40 and 14:10 HALO, respectively, meaning that maximum activity occurred 16 h after the maximum observed expression. These results, revealing the existence of a circadian rhythm in DPD expression, should stimulate further studies to enhance our understanding of the molecular mechanisms involved in the circadian regulation of the DPD enzyme.