Studies on glucose synthesis by rat liver and kidney cortex slices

Net glucose production has been studied in liver and kidney cortex slices from normal fasted rats. Only a small amount of net glucose synthesis was observed with individual substrates such as lactate, glycerol, phosphoenol pyruvate, succinate, alanine, aspartate and glutamate. With fructose, an increase in glucose synthesis was observed with an increase in concentration, but similar results were not obtained with lactate. Further studies with combinations of substrates indicate that net glucose synthesis occurs in the following decreasing order: glutamate, glycerol and pyruvate; glutamate and pyruvate; glutamate, glycerol and lactate. Glucose formation by kidney slices was slightly less than that observed in liver. Both tissues gave a similar response to the various substrates tested.