Diffusion of reactive metabolites out of hepatocytes: studies with bromobenzene

Journal Article · Wed Feb 01 04:00:00 EST 1984 · J. Pharmacol. Exp. Ther.; (United States)

OSTI ID:6722414

Monks, T J; Lau, S S; Gillette, J R

We have developed a simple experimental technique which allows the determination of the relative rates of intracellular inactivation of chemically reactive metabolites and their diffusion out of isolated rat hepatocytes. By using bromobenzene as a model compound we have demonstrated that bromobenzene-3, 4-oxide generated within hepatocytes is sufficiently stable to leave the endoplasmic reticulum in which it is formed, traverse the cytoplasm and cross the cell membrane to the external environment. The addition of varying amounts of protein, which serves as an external sink to trap the epoxide as a covalently bound adduct, permits the calculation of the relative rates at which the epoxide is inactivated within the cells and diffuses out of the cells. As much as 35% of bromobenzene-3,4-oxide is capable of leaving hepatocytes and being trapped as a covalently bound adduct to glutathione (GSH)-transferase B. The extensive diffusion of bromobenzene-3,4-oxide may play an important role in the intercellular toxicity of this compound within the liver and perhaps may contribute to extrahepatic toxicity. The addition of GSH-transferase B to isolated hepatocyte suspensions caused a decrease in the formation of the 3,4-dihydrodiol, p-bromophenol and o- and p-bromophenol glucuronides, an increase in the formation of bromobenzene GSH conjugates, but did not affect intracellular covalent binding. Kinetic analyses of the data revealed that, in the absence of GSH-transferase B, nearly all of the bromobenzene GSH conjugates are formed within hepatocytes as the epoxide is formed, whereas rearrangement of bromobenzene-3,4-oxide to p-bromophenol and hydration to bromobenzene-3,4-dihydrodiol occurs almost exclusively outside the hepatocytes.

• Research Organization: National Heart, Lung and Blood Inst., Bethesda, MD
• OSTI ID: 6722414
• Journal Information: J. Pharmacol. Exp. Ther.; (United States), Journal Name: J. Pharmacol. Exp. Ther.; (United States) Vol. 228:2; ISSN JPETA
• Country of Publication: United States
• Language: English

Related Subjects

560301* -- Chemicals Metabolism & Toxicology-- Cells-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
AROMATICS
BODY
BROMINATED AROMATIC HYDROCARBONS
DIFFUSION
DIGESTIVE SYSTEM
DRUGS
ENZYMES
EPOXIDES
GLANDS
GLUTATHIONE
HALOGENATED AROMATIC HYDROCARBONS
INACTIVATION
LIVER
MAMMALS
METABOLISM
METABOLITES
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
RADIOPROTECTIVE SUBSTANCES
RATS
RODENTS
SOMATIC CELLS
TRANSFERASES
VERTEBRATES