Lack of an inducible effect of dietary soy isoflavones on the mRNA abundance of hepatic cytochrome P-450 isozymes in rats.
Modulation of the activity and content of cytochrome P-450 (CYP) in hepatic microsomes may be important to human health since these enzymes activate and inactivate a wide range of xenobiotics and food components. Regulation of the inducibility of most CYPs involves transcriptional regulation and post-transcriptional mRNA stabilization. We examined in the present study the effect of dietary soy isoflavone (0-300 mg of isoflavone/kg of diet) on the mRNA abundance of rat hepatic CYP1A1, CYP1A2, CYP2B1/2, CYP2C11, CYP2E1, CYP3A1, CYP3A2 and CYP4A1 by quantitative competitive RT-PCR and real-time monitored RT-PCR. A fermented soy extract containing 155 mg/g of genistein, 127 mg/g of daidzein, and other minor isoflavones was used as the isoflavone source. The dietary soy isoflavone had no affect on the hepatic mRNA abundance of these CYPs. The results by both methods were well matched and indicate that the dietary soy isoflavone did not cause the induction of CYPs by transcriptional step-up regulation or post-transcriptional mRNA stabilization.
Kishida
Taro
T
Department of Biological Resources, Faculty of Agriculture, Ehime University, Matsuyama, Japan. kishida@agr.ehime-u.ac.jp
Nagamoto
Manabu
M
Ohtsu
Yohhei
Y
Watakabe
Miho
M
Ohshima
Daisuke
D
Nashiki
Kunitaka
K
Mizushige
Takafumi
T
Izumi
Tohru
T
Obata
Akio
A
Ebihara
Kiyoshi
K
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D021983:Cyclophilins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D004435:Eating / Q000187:drug effects; D004790:Enzyme Induction; D005260:Female; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D007529:Isoflavones / Q000378:metabolism / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013025:Glycine max / Q000737:chemistry* / Q000378:metabolism
D007211:Indoles; D007527:Isoenzymes; D007529:Isoflavones; D010936:Plant Extracts; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C016517:indole-3-carbinol; D021983:Cyclophilins