Stimulation of gluconeogenesis by propylene glycol in the fasting rat

Abstract Propylene glycol, a compound metabolically active as a carbohydrate, is often employed as part of the vehicle for pharmacological preparations. Since the latter may be administered to experimental animals which are used in studies concerned with carbohydrate metabolism, the effects of small doses of propylene glycol on gluconeogenesis were determined. The intramuscular administration of propylene glycol provoked a dose dependent increase in liver glycogen, rate of glycogen synthesis, and blood glucose concentration. Maximal effects occured within 90 minutes and the values returned to control levels within 3 hours. Quinolinic acid, a weak inhibitor of basal gluconeogenesis, was found to markedly inhibit the increased gluconeogenesis resulting from propylene glycol administration. These findings suggest that the elevated gluconeogenesis produced by propylene glycol does not follow the same metabolic pattern as the basal gluconeogenesis and that rats receiving this compound cannot be considered as metabolic equivalents to untreated animals with respect to carbohydrate metabolism.