The effect of dietary sulfur-containing amino acids on the activity of drug-metabolizing enzymes in rat-liver microsomes.
Male Wistar rats were fed either a balanced diet whose protein source was a mixture of amino acids (diet 1), or a similar diet which differed only in having 48% less the quantity of the sulfur-containing amino acids methionine and cystine (diet 2). The diets were given either continuously for 1 month or for 15 days after a protein-free diet. Both diets 1 and 2 permitted good growth of rats and relatively stable microsomal protein content. Protein depletion decreased the total proteins, total phospholipids, and cytochrome P-450 content, and it strongly increased UDP-glucuronosyltransferase activity in rat-liver microsomes. Repletion with diet 1 restored those values, to the level found in control rats. However, diet 2, given continuously induced an increase in UDP-glucuronosyltransferase activity and in the cytochrome P-450 concentration. Since high UDP-glucuronosyltransferase activity was related to lessened amounts of sulfur-containing amino acids in the diet, we discuss the possible effect of methionine and cystine on the regulation of glucuronoconjugation in relation to sulfoconjugation.
D000596:Amino Acids / Q000008:administration & dosage; D000603:Amino Acids, Sulfur / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight; D003553:Cystine / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology*; D010743:Phospholipids / Q000378:metabolism; D011488:Protein Deficiency / Q000178:diet therapy / Q000378:metabolism; D051381:Rats
D000596:Amino Acids; D000603:Amino Acids, Sulfur; D010743:Phospholipids; D003553:Cystine; D003577:Cytochrome P-450 Enzyme System; D008715:Methionine; D014453:Glucuronosyltransferase