Circadian rhythm in dihydropyrimidine dehydrogenase activity and reduced glutathione content in peripheral blood of nasopharyngeal carcinoma patients.
Dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme of 5-fluorouracil (5-FU) catabolism. Glutathione (GSH) is a tripeptide involved in platinum complex detoxification. This study explored the circadian rhythms of DPD activity and GSH concentration in the peripheral blood of 16 patients with histologically proven nasopharyngeal carcinoma (NPC) in order to guide the establishment of chronotherapeutic schedules for this cancer. DPD activity and GSH concentration were determined by high performance liquid chromatography (HPLC). Both variables displayed significant circadian rhythms (Cosinor analysis: p = 0.009 and 0.012, respectively). Peak DPD activity occurred at about 02:30 h; whereas, peak GSH concentration occurred around 12:40 h. The differences between the peak and nadir mean values were 25.5% and 38.7%, respectively. The study showed that the circadian rhythms in DPD activity and GSH concentration in Chinese NPC are similar to those reported for western patients with colorectal cancer, despite the differences in race and kinds of cancer. These findings imply that the chronotherapeutic schedule of 5-FU and platinum used to treat European colorectal cancer patients probably is applicable to Chinese NPC patients.
Zeng
Zhao-Lei
ZL
Cancer Center, SUN Yat-sen University, Guangzhou, P.R. China.
Sun
Jian
J
Guo
Ling
L
Li
Su
S
Wu
Ming-wei
MW
Qiu
Fang
F
Jiang
Wen-qi
WQ
Lévi
Francis
F
Xian
Li-jian
LJ
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000097:blood* / Q000201:enzymology; D002940:Circadian Rhythm; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000097:blood*; D005260:Female; D005978:Glutathione / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000097:blood* / Q000201:enzymology
D042943:Dihydrouracil Dehydrogenase (NADP); D005978:Glutathione