Related Experiment Video
Updated: Jul 20, 2026

The Dimethylnitrosamine Induced Liver Fibrosis Model in the Rat
Published on: June 17, 2016
Hydroxylation of dibutylnitrosamine in the human liver and intestinal microsomal fractions
Abstract:
The metabolism of the bladder carcinogen N-nitroso-di-n-butylamine (NDBA) was studied in microsomal preparations of tissues of patients of both sexes, aged 59-69 years undergoing abdominal surgery. Samples of liver, ileum, and colon were of normal histological appearance. For comparison, samples of rat liver and small intestinal mucosa microsomes were included in the study. Using 1-14C-labeled NDBA, the biotransformation to hydroxylation products retaining the nitroso group, NDBA-2-OH, NDBA-3-OH, and NDBA-4-OH, respectively, was investigated by reversed phase HPLC. In order to separate these metabolites, pooled samples were analysed by normal phase HPLC. The rate of hydroxylation of NDBA was found to be 5.5 times higher in rat liver microsomes compared to those from human liver (2.86 +/- 0.29 vs 0.52 +/- 0.03 nM X min-1 X mg-1). NDBA-3-OH proved to be the major metabolite formed (greater than 80% of total metabolites). The metabolism of NDBA was low but detectable in seven out of nine specimens of human gut, 0.1-0.5 nM X mg-1 in 1 h of incubation, and of the same order of magnitude in rat intestinal tissue (0.4-0.6 nM X mg-1).
More Related Videos
07:38A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
Published on: September 25, 2017
09:33Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
Published on: March 20, 2018
Related Concept Videos
2° Amines to N-Nitrosamines: Reaction with NaNO2
Drug Biotransformation: Overview
Drug Metabolism: Phase II Reactions
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
Phase II Reactions: Glucuronidation
Phase II Reactions: Acetylation Reactions
The substrates for acetylation are typically drugs or their metabolites with an amino, sulfonamide, or hydrazine functional group. Acetylation can occur at several points in the drug molecule, including primary, secondary, and...