Regulation of glutathione S-transferase enzymes in primary cultures of rat hepatocytes maintained under various matrix configurations

• Published in: Toxicology in vitro 2000-04, Vol.14 (2), p.101-115
• Main Authors: LeCluyse, E.L, Ahlgren-Beckendorf, J.A, Carroll, K, Parkinson, A, Johnson, J
• Format: Article
• Language: English
• Subjects: Animals; beta-Naphthoflavone - pharmacology; Cells, Cultured; Chromatography, High Pressure Liquid; Cytosol - drug effects; Cytosol - enzymology; Dexamethasone - pharmacology; enzyme induction; Enzyme Induction - drug effects; Enzyme Inhibitors - pharmacology; extracellular matrix; Extracellular Space - drug effects; Extracellular Space - enzymology; glutathione S-transferase; Glutathione Transferase - antagonists & inhibitors; Glutathione Transferase - biosynthesis; Glutathione Transferase - metabolism; hepatocyte culture; Liver - cytology; Liver - drug effects; Liver - enzymology; Male; Phenobarbital - pharmacology; rat hepatocytes; Rats; Rats, Sprague-Dawley
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/S0887-2333(00)00007-2

Primary rat hepatocytes were cultured under various matrix and media conditions and examined after 1 week for the expression and regulation of cytosolic glutathione S-transferase (GST) enzymes. Striking effects on cell morphology were observed in relation to the different matrix conditions, whereas media effects were less prominent. Hepatocytes cultured in serum-free Dulbecco's modified Eagle's medium (DMEM) or modified Chee's medium (MCM) maintained similar levels of total GST protein regardless of the matrix configuration or corresponding cell integrity. However, HPLC analysis showed a differential expression pattern of individual GST subunits in both a time- and medium-dependent fashion. A variable, but pronounced, matrix and medium effect was observed on the induction of total GST expression by various prototypical inducers. Dexamethasone (10 μ m) induced subunits A2, M1 and M2 in a medium- and matrix-dependent fashion, whereas phenobarbital (100 μ m) induced significantly only subunit A2. β-Naphthoflavone (50 μ m) suppressed all GST subunit expression except subunit P1, which was induced in a matrix- and medium-dependent fashion. These studies show that total basal level expression of GSTs in vitro is reflective of a concomitant increase in μ and π class subunits and a decrease in α class subunits. Moreover, the matrix and medium conditions influence both the basal and inducible expression of GST subunits in cultured rat hepatocytes.