Beedham C, Padwick D J, al-Tayib Y, Smith J A
Pharmaceutical Chemistry, School of Pharmacy, University of Bradford, West Yorkshire, U.K.
Biochem Pharmacol. 1989 May 1;38(9):1459-64. doi: 10.1016/0006-2952(89)90185-8.
The activities of the xenobiotic metabolizing enzymes, aldehyde oxidase and xanthine oxidase, were determined in partially purified fractions of adult guinea-pig liver at given times in the day or night. A marked circadian variation in aldehyde oxidase activity was observed with several substrates (phthalazine, phenanthridine, N-phenylquinolinium and 3,4-dihydro-4-hydroxy-3-methyl-2-quinazolinone). The main peak occurred at 0300 hr with minimum activity from 1200 to 1800 hr, the differences between rhythmic extremes being statistically significant (P less than 0.005). Xanthine oxidase activity also exhibited a daily rhythm but with a lower amplitude. Guinea-pig serum melatonin showed a synchronous circadian fluctuation with peak values at 0300 hr falling throughout the day to a minimum at 1800 hr. Exogenously administered melatonin caused a significant increase in aldehyde oxidase activity at 0900 and 1200 hr and in xanthine oxidase activity at 0900 hr. It was concluded that melatonin concentrations may be related to the circadian variation in liver molybdenum hydroxylase activity.
在白天或夜晚的特定时间，测定成年豚鼠肝脏部分纯化组分中异源物代谢酶醛氧化酶和黄嘌呤氧化酶的活性。观察到醛氧化酶活性对几种底物（酞嗪、菲啶、N - 苯基喹啉鎓和3,4 - 二氢 - 4 - 羟基 - 3 - 甲基 - 2 - 喹唑啉酮）存在明显的昼夜节律变化。主要峰值出现在03:00，12:00至18:00活性最低，节律极端值之间的差异具有统计学意义（P小于0.005）。黄嘌呤氧化酶活性也呈现每日节律，但幅度较小。豚鼠血清褪黑素呈现同步的昼夜波动，峰值在03:00，全天逐渐下降至18:00达到最低值。外源性给予褪黑素在09:00和12:00时使醛氧化酶活性显著增加，在09:00时使黄嘌呤氧化酶活性显著增加。得出的结论是，褪黑素浓度可能与肝脏钼羟化酶活性的昼夜变化有关。
