1. Gluconeogenesis from lactate in the perfused liver is stimulated by glucagon and the catecholamines. It is suggested that this effect has physiological significance.
2. The effect of the hormones on gluconeogenesis appears to be mediated by cyclic 3',5'-AMP.
3. The hormones (or cyclic 3',5'-AMP) activate more than one step in the pathway of lactate to glucose. The changes in the concentration of metabolic intermediates induced by the hormones are consistent with activations of phosphopyruvate carboxylase and the hexose phosphate phosphatases.