Comparison of the glucuronidation ability of liver microsomes from rats treated with 3-methylcholanthrene or phenolic antioxidants.
1. UDP-glucuronyltransferase activity was studied in hepatic microsomal preparations isolated from female Sprague-Dawley rats treated with either 3-methylcholanthrene, butylated hydroxyanisole, propyl gallate, ethoxyquin or a combination of 3-methylcholanthrene and butylated hydroxyanisole. 2. The substrates p-nitrophenol, 1-naphthol and phenolphthalein were used. With p-nitrophenol all treatments, except propyl gallate, caused a significant increase in activity over the control value; the combined treatment of 3-methylcholanthrene and butylated hydroxyanisole gave an additive response when compared to each treatment used singly. With 1-naphthol as substrate, 3-methylcholanthrene and 3-methylcholanthrene + butylated hydroxyanisole caused 8-fold increases in activity compared to the 2-3 fold increased caused by the other treatments. When phenolphthalein was used, all treatments increased activity to the same extent. 3. When the assays were repeated with various concentrations of each substrate, the results revealed that, except where phenolphthalein was used, distinguishable differences in the activity of each microsomal preparation were discernible, the most significant being the bimodal response of each preparation to low and high concentrations of p-nitrophenol.
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D005260:Female; D005965:Glucuronates / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000378:metabolism; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D020113:Phenolphthalein; D010635:Phenolphthaleins / Q000494:pharmacology; D010636:Phenols / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D000975:Antioxidants; D005965:Glucuronates; D010635:Phenolphthaleins; D010636:Phenols; D008748:Methylcholanthrene; D020113:Phenolphthalein; D014453:Glucuronosyltransferase