餵食炸油對天竺鼠肝中 cytochrome P450 及其他解毒酵素活性之影響
Effects of Deteriorated Frying Oil on Liver Cytochrome P450 and
Other Detoxifying Enzymes Activity in Guinea Pigs
中文摘要 本研究的目的欲探討餵食炸油於無法合成維生素 C 的天竺鼠時，對天竺鼠體內 解毒酵素系統的影響。將新鮮黃豆油在 200±5℃下油炸薯條，每天油炸 6 小時， 連續 4 天共油炸 24 小時，作為實驗用炸油。將新鮮油、炸油分別以 15％重量混 入不含維生素 C 的純化飼料，再分別添加 300ppm 維生素 C 作為 F300、D300 組 的飼料，餵養剛離乳之雄性天竺鼠，共為期 17 週。結果顯示，炸油組(D300)生 長及攝食效率較差，血漿及肝腎組織中維生素 C 含量均明顯低於 F300 組，而肝、 腎組織中 TBARS(Thiobarbituric acid reactive substances)含量較高。餵食炸油之天 竺鼠肝中 UDP-Glucuronyl-Transferase(UGT)活性高於新鮮油組，Glutathione S-Transferase(GST)活性於兩組間則沒有差異。且炸油組肝微粒體中 cytochrome P450 含量明顯增加；cytochrome P450 相關酵素：NADPH-cytochrome c reductase 活性亦明顯高於新鮮油組。在測定異構酉每特性方面，代表 CYP1A1 的 EROD 之活性以炸油組較高，代表 CYP2B 的 PROD 之活性則沒有差異。但經由
SDS-PAGE 及 Western immunoblotting 之檢定，發現 CYP1A1 isoform 之表現於炸 油組及新鮮油組間並無顯著地差異。由上述結果推測，餵食炸油會消耗天竺鼠體 內維生素 C，並可增加（誘發）天竺鼠肝中解毒酵素系統相關酵素之活性，但為 何種 cytochrome P450 之異構酉每仍須進一步地探討。
英文摘要
The purpose of this study is to investigate the effect of deteriorated frying oil (DFO) on the liver detoxifying enzyme system of guinea pigs. DFO sample was obtained by flying potato chips in soybean oil under 200±5℃ for 24 hours. Fifteen male weaning guinea pigs were fed 15% DFO or fresh soybean oil supplemented with 300 ppm ascorbic acid diet for 12 weeks. It was shown that guinea pigs fed the DFO diet (D300) had worse growth and lower feed efficiency than in the control (F300). The contents of vitamin C in plasma, liver and kidney of D300 were lower than the the control (F300). Besides, the contents of TBARS (Thiobarbituric acid reactive substance) in liver and kidney of D300 were higher than F300. The activity of liver UGT
(UDP-Glucuronyl-Transferase) of D300 was higher than F300 and there was no difference between two groups in GST (Glutathione-S-Transferase) activity. By the way, the content of total cytochrome P450 (CYP450) and the activity of
NADPH-cytochrome c reductase of D300 were increased significantly. In the detection of characterisitics of cytochrome P450 isozyme, the activity of EROD
(Ethoxyresorufin O-deethylase) which presents CYP1A1 was higher in D300 than in F300. There was no difference in the activity of PROD (Pentoxyresorufm
O-dealkylase) which presents CYP2B between two groups. However, it was founded that the amount of CYP1A01 isoform of D300 did not differ apparently from it of F300 through the SDS-PAGE and western immunoblotting.
Our results demonstrated that the activities of relative enzymes in the liver
detoxifying enzymes system of guinea pigs could be induced by DFO feeding, but it needs the advanced research to identify the major type of cytochrome P450 isozyme which works under this condition.
