Evidence for possible interrelationship between gluconeogenesis and ketogenesis?

Effects of ketogenic substrates on gluconeogenesis by rat hepatocytes were examined. D,L-3-Hydroxybutyrate (5 mM) stimulated gluconeogesis from lactate by 41%, the effect being the same as that of 5 mM acetate (43%). Acetoacetate up to 40 mM had no stimulating effect; conversely, it partially or completely abolished the observed stimulating effects of acetate, 3-hydroxybutyrate, or oleate. 3-Hydroxybutyrate also stimulated gluconeogenesis from serine by 70%, the effect being much higher than that of acetate (35%). No effect of 3-hydroxybutyrate or acetate on gluconeogenesis from pyruvate was seen. It is proposed that, in intact liver cells, pyruvate is transported into mitochondria in exchange for intramitochondrially generated acetoacetate, and that the mechanism proposed may be of physiological importance.