Metanil yellow: a bifunctional inducer of hepatic phase I and phase II xenobiotic-metabolizing enzymes.
Metanil yellow, a non-permitted food colour, has been found in various foodstuffs. The induction potential of metanil yellow on hepatic microsomal cytochrome P-450 (P-450)-dependent monooxygenases and cytosolic detoxification enzymes, namely, glutathione S-transferase (GST) and quinone reductase (QR), was investigated. Oral administration of metanil yellow (430 mg/kg body weight) to four animals for seven days caused significant induction of hepatic P-450 (48%) and its dependent aryl hydrocarbon hydroxylase (100%) activity and cytosolic GST (136%) and QR (92%) activities. Parenteral administration of metanil yellow (80 mg/kg body weight) to another set of four animals for 3 days resulted in higher induction of ethoxyresorufin-O-deethylase (228%) as compared to other monooxygenases (64-92%), while GST and QR were also found to be induced (59-95%). Spectra of metanil yellow-induced microsomes showed an increase in P-450 with a shift of 2.2 nm in the soret region. The results suggest that metanil yellow acts as a bifunctional inducer of specific isozymes of P-450 and cytosolic enzymes and thus may involve the cytosolic aryl hydrocarbon (Ah) receptor for this type of induction.
Das
M
M
Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow, India.
Ramchandani
S
S
Upreti
R K
RK
Khanna
S K
SK
D000284:Administration, Oral; D000818:Animals; D001391:Azo Compounds / Q000633:toxicity*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D004790:Enzyme Induction; D005505:Food Coloring Agents / Q000633:toxicity*; D005982:Glutathione Transferase / Q000096:biosynthesis*; D007274:Injections, Intraperitoneal; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
D001391:Azo Compounds; D005505:Food Coloring Agents; C005108:metanil yellow; D003577:Cytochrome P-450 Enzyme System; D016660:NAD(P)H Dehydrogenase (Quinone); D005982:Glutathione Transferase