Related Experiment Video

Updated: Aug 13, 2026

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
09:33

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling

Published on: March 20, 2018

Glutathione-dependent bioactivation of xenobiotics: implications for mutagenicity and carcinogenicity

M W Anders1

  • 1Department of Pharmacology, University of Rochester, New York 14642.

Princess Takamatsu Symposia
|January 1, 1990
PubMed

Insights

Glutathione conjugate formation activates mutagens and carcinogens. This bioactivation pathway is crucial for understanding the toxicity and carcinogenicity of various chemicals, including haloalkenes and chemotherapeutic agents.

Area of Science:

  • Toxicology
  • Biochemistry
  • Carcinogenesis

Background:

  • Glutathione conjugate formation is a key bioactivation mechanism.
  • Several classes of compounds are metabolized to direct-acting cytotoxic or mutagenic conjugates.
  • This pathway is implicated in the toxicity of various chemicals.

Purpose of the Study:

  • To review the role of glutathione conjugate formation in chemical bioactivation.
  • To highlight the multistep pathway for nephrotoxic haloalkenes.
  • To discuss the implications for chemical carcinogenesis and drug toxicity.

Main Methods:

  • Literature review of studies on glutathione metabolism and chemical toxicity.
  • Analysis of metabolic pathways involving glutathione conjugates.
  • Correlation of bioactivation pathways with mutagenicity and carcinogenicity data.

Main Results:

  • Dihalomethanes and related compounds form direct-acting cytotoxic/mutagenic glutathione conjugates.
  • Haloalkenes undergo hepatic S-conjugate formation, renal translocation, and beta-lyase bioactivation.
  • Fluoroalkene conjugates are cytotoxic; chloroalkene conjugates are cytotoxic and mutagenic.
  • Beta-lyase bioactivation explains nephrocarcinogenicity of certain haloalkenes.
  • Glutathione conjugates are implicated in the mutagenicity of Trp-P-2 and DNA damage by other compounds.
  • Glutathione plays a role in the toxicity of several cancer chemotherapeutic agents.

Conclusions:

  • Glutathione conjugate formation is a significant bioactivation pathway for mutagens and carcinogens.
  • The cysteine conjugate pathway in the kidney is critical for haloalkene nephrotoxicity and nephrocarcinogenicity.
  • Understanding these pathways is vital for assessing chemical risks and developing therapeutic strategies.

More Related Videos

Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases14:57

Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases

Published on: October 10, 2020

Rapid Quantification of Oxidized and Reduced Forms of Glutathione Using Ortho -phthalaldehyde in Cultured Mammalian Cells In Vitro03:35

Rapid Quantification of Oxidized and Reduced Forms of Glutathione Using Ortho -phthalaldehyde in Cultured Mammalian Cells In Vitro

Published on: June 28, 2024

Related Concept Videos

Mutagenicity and Carcinogenicity01:25

Mutagenicity and Carcinogenicity

Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...
Drug Biotransformation: Overview01:16

Drug Biotransformation: Overview

Pharmaceutical substances known as xenobiotics are predominantly lipophilic and nonionized. This enables them to permeate lipid bilayers, such as cell membranes, and interact with intracellular target receptors. Lipophilic drugs have an advantage in crossing biological barriers and reaching their intended sites of action. However, lipophilic drugs often have a restricted capacity for renal expulsion or elimination from the body. When these drugs enter the kidneys and undergo glomerular...
Drug Metabolism: Phase II Reactions01:14

Drug Metabolism: Phase II Reactions

Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation01:22

Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation

Glutathione, a tripeptide made up of glutamate, cysteine, and glycine, is a critical player in the detoxification of drugs and xenobiotics via a process known as glutathione conjugation or mercapturic acid formation. This phase II biotransformation reaction involves the covalent binding of glutathione to a drug or its metabolite, enhancing the compound's water solubility and enabling its excretion.
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase01:27

Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase

Phase II biotransformation reactions are essential for detoxifying and eliminating xenobiotics, including many pharmaceutical compounds. These reactions typically involve conjugation, the covalent attachment of polar endogenous groups such as glucuronic acid, sulfate, methyl, or acetyl moieties to functional groups introduced during Phase I metabolism. The resulting conjugates are more water-soluble, enabling efficient renal or biliary excretion.The major classes of Phase II enzymes include...
Bioactivation and Tissue Toxicity01:25

Bioactivation and Tissue Toxicity

Bioactivation is a metabolic process that transforms less reactive substances into highly reactive metabolites, initiating tissue toxicity. This transformation can lead to various toxic effects, including carcinogenesis and teratogenesis. Reactive metabolites are classified into two main types: electrophiles and free radicals.Electrophiles are electron-deficient species and are produced primarily by the enzyme cytochrome P-450 during the metabolism of compounds containing carbon, nitrogen, or...