[Gluconeogenesis, ketogenesis, and ureogenesis in isolated hepatocytes from diabetic rats: effects of insulin]

The intermediary metabolism in hepatocytes isolated from diabetic rats has been studied. The incubation medium is a Krebs-Henseleit buffer containing albumin-bound oleate (1 mmol/l). The high rates of gluconeogenesis, ureogenesis and ketogenesis were consistent with the diabetic state of the rats. Insulin (8 X 10(-7) mol/l) decreased glucose and urea productions from alanine (10 mmol/l) by 30%; beta-hydroxybutyrate production, oleate utilization and malate efflux (calculated) from mitochondria were also decreased. No effect of insulin was found with lactate (10 mmol/l) as gluconeogenic substrate. The glycogen content of cells was constant during the time of incubation (4h). These data suggest that the oxidation-reduction state of mitochondria and the cytoplasmic oxaloacetate concentration could be important factors in the action of insulin.