- 作者: 翁芸芳; 朱致民; 湯弘吉; 林仁混; 翁祖輝
- 作者服務機構: 國立臺灣大學醫學院生化學研究所; 臺灣省水產試驗所竹北分所
- 中文摘要:
研究吳郭魚單氧?之主要動機在於此種魚有耐污染之特性。未處理之吳郭魚中肝微粒細胞色素P-450含量及單氧?
活性較田鼠肝P-450量及?活性為低。將吳郭魚用3-甲基瞻蔥處理後,肝P-450含量增高2倍。同時,7-ethoxyresorufin
O-去乙基,苯駢芘羥化及7-乙氧基香豆素O-去乙基等單氧?活性則分別升高19,7及3倍。此多環芳香羥處理對N,
N-雙甲基亞硝胺去甲基?活性無影響。3-甲基瞻蔥使細胞色素b5含量增高2倍,但不改NADPH-細胞色素c還原?
之活性。在一氧化碳差異光譜中,對照組微粒體之最高吸收?在450 nm,而3-甲基膽蔥處理組之吸收?轉移至449
nm。微粒體膠電泳結果展示3-甲基膽蔥處理組在P-450分子量區域間一蛋白染色帶濃度增加。以上結果顯示吳郭魚肝
含完整單氧?系統,而3-甲基膽蔥能誘導其單氧?活性。本實驗室將繼續探討利用吳郭魚單氧?做為河川中多環芳香
羥類生化指標之可行性。t - 英文摘要: That tilapia has the ability to persist in highly polluted habitats prompted us to study the mono-oxygenase system of the fish. Liver microsomes prepared from the untreated tilapias showed low levels ofcytochrome P-450 and dependent monooxygenase activity, relative to those found in the hamster. Pre-treatment of the fish with 3-methylcholanthrene (3-MC) caused a 2-fold increase of cytochrome P-450content in liver microsomes. The increase of the hemoprotein was associated with 19-, 7- and 3-foldinduction of 7-ethoxyresorufin O-deethylase, benzo(a)pyrene hydroxylase and 7-ethoxycoumarin O-deethylase activities, respectively. Pretreatment with the polycyclic aromatic hydrocarbon had no significanteffect on N-nitrosodimethylamine demethylase activity. In addition, 3-MC caused a 2-fold increase ofcytochrome b5 content without affecting NADPH-cytochrome c reductase activity. Spectral analysis ofliver microsomes showed that the Soret maximum in CO-difference spectrum shifted from 450 nm incontrol fish to 449 nm in 3-MC-treated animals. Gel electrophoresis of the microsomes revealed that 3-MCcaused a marked increase in the intensity of the protein band(s) in the cytochrome P-450 molecular weightregion. These data suggest that a complete monooxygenase system exists in the tilapia and the enzymesystem is responsive to the stimulatory effect of 3-MC. Studies are in progress to investigate the possibilityof using tilapia monooxygenase as a biochemical indicator for the environmentally derived polycyclicaromatic hydrocarbons.
- 中文關鍵字: 3-methylcholanthrene; cytochrome P-450; monooxygenase; enzyme induction; fish
- 英文關鍵字: --