title: Assessment of energetic costs of AhR activation by β-naphthoflavone in rainbow trout (Oncorhynchus mykiss) hepatocytes using metabolic flux analysis.
abstract: Exposure to environmental contaminants such as activators of the aryl hydrocarbon receptor (AhR) leads to the induction of defense and detoxification mechanisms. While these mechanisms allow organisms to metabolize and excrete at least some of these environmental contaminants, it has been proposed that these mechanisms lead to significant energetic challenges. This study tests the hypothesis that activation of the AhR by the model agonist β-naphthoflavone (βNF) results in increased energetic costs in rainbow trout (Oncorhynchus mykiss) hepatocytes. To address this hypothesis, we employed traditional biochemical approaches to examine energy allocation and metabolism including the adenylate energy charge (AEC), protein synthesis rates, Na(+)/K(+)-ATPase activity, and enzyme activities. Moreover, we have used for the first time in a fish cell preparation, metabolic flux analysis (MFA) an in silico approach for the estimation of intracellular metabolic fluxes. Exposure of trout hepatocytes to 1μM βNF for 48h did not alter hepatocyte AEC, protein synthesis, or Na(+)/K(+)-ATPase activity but did lead to sparing of glycogen reserves and changes in activities of alanine aminotransferase and citrate synthase suggesting altered metabolism. Conversely, MFA did not identify altered metabolic fluxes, although we do show that the dynamic metabolism of isolated trout hepatocytes poses a significant challenge for this type of approach which should be considered in future studies.
authors: Ottawa-Carleton Institute of Biology, Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada. naultran@msu.edu
authors: Rance
authors: R
authors: Nault
authors: Hiba
authors: H
authors: Abdul-Fattah
authors: Gleb G
authors: GG
authors: Mironov
authors: Maxim V
authors: MV
authors: Berezovski
authors: Thomas W
authors: TW
authors: Moon
mesh_terms: D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D017686:Oncorhynchus mykiss; D014176:Protein Biosynthesis / Q000187:drug effects; D011506:Proteins; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists* / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D019324:beta-Naphthoflavone / Q000494:pharmacology*
chemical_list: D011506:Proteins; D018336:Receptors, Aryl Hydrocarbon; D019324:beta-Naphthoflavone; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Energetic costs; Hepatocytes; Metabolic flux analysis; Rainbow trout; β-Naphthoflavone