Effects of Triadimefon on the Metabolism of Cultured Hepatocytes

The liver, being the major site of metabolism, plays a critical role in xenobiotic biotransformation and clearance. Quantifying the links between central hepatic and xenobiotic metabolism is critical to understanding toxicant-induced hepatic injury. Conazoles are a class of azole fungicides used to prevent fungal growth in fruits, vegetables and seeds, and for the treatment of fungal infections. Certain conazoles (such as triadimefon) are found to be tumorigenic in rats and mice. In this study, cultured primary rat hepatocytes were treated to varying doses (less than or equal to 0.3 mM) of triadimefon on a temporal basis with daily media change. Following exposure, supernatant was collected daily for 3 days and concentration of various metabolites (triadimefon, glucose, urea, albumin, amino acids, fatty acids, cholesterol etc.) in the media and supernatant were quantified. Albumin production was reduced in 0.3 mM triadimefon treated cells by the end of three days whereas urea production was not significantly affected. Metabolic network flexibility analysis (MNFA) demonstrated that by the end of the three day period, 0.3 mM triadimefon treated cells exhibited a major switch in hepatic metabolism by producing glucose, instead of glucose consumption. We also observed fatty acid oxidation instead of fatty acid synthesis in 0.3 mM triadimefon treated cells. Fatty acid oxidation also caused higher flux through the TCA cycle which in turn drove gluconeogenesis in these cells. It is likely that fatty acid oxidation is active in order to supply energy that is required by the phase I oxidation of triadimefon detoxification.