Establishment and characterization of a novel method for evaluating gluconeogenesis using hepatic cell lines, H4IIE and HepG2.

The liver gluconeogenic pathway is recognized as a target for treating diabetes mellitus. In this study, we attempted to establish a new method to evaluate gluconeogenesis using rat H4IIE hepatoma cells. High-density preculture and exposure to hypertonic solutions, which are known to upregulate the expression of gluconeogenic genes, enhanced glucose release (GR) promoted by gluconeogenic substrates (GS: 1 mM pyruvate and 10 mM lactate). Our method was also applicable to the human hepatoma HepG2 cells. Measurement of glycogen content in HepG2 cells revealed that GR was compensated by glycogenolysis in the basal state and was generated by gluconeogenesis in the presence of GS. The optimized conditions increased the expression of gluconeogenic genes in HepG2 cells. Insulin and metformin dose-dependently inhibited GR and 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) increased it. These results suggest that the present method is useful to evaluate the effects of nutrients, hormones and hypoglycemic agents on hepatic gluconeogenesis.