Intestinal and hepatic mixed function oxidase activity in rats fed methionine and cysteine-free diets.

Abstract

SummaryIntestinal and hepatic mixed function oxidase (MFO) activity was studied in rats fed sulfur amino acid free diets. Male, Sprague-Dawley rats (~140 g) were randomly assigned to three diets containing l-amino acids as the only source of nitrogen and fed for 4 days. The treatments were the control diet fed ad libitum (C), the control diet minus methionine and cysteine (M), and the control diet pair fed (P) with the M-deficient partners. There were no significant differences in total microsomal protein in the first 25 cm of the small intestine but total liver microsomal protein was depressed by decreased food intake and by the sulfur amino acid deficiency (P < 0.05). Intestinal aryl hydrocarbon hydroxylase (AHH) specific activity (nmol 3-OH BP/30 min/mg) was (C) 2.30 ± 0.27, (P) 1.75 ± 0.28, (M) 0.65 ± 0.06, and hepatic AHH specific activity was (C) 15.9 ± 2.1, (P) 16.3 ± 2.4, (M) 4.6 ±1.3. The data show that sulfur amino acid deficiency causes a similar reduction in intestinal and hepatic MFO activity...