Antiketogenic action of fructose in man

The effect of fructose infusion (10 gm. every five minutes as a bolus followed by 0.5 gm. per kilogram X hours) on arterial concentrations and hepatic balances of ketones was studied in four juvenile diabetics 24 hours after the withdrawal of insulin. Arterial and hepatic venous concentrations of beta-hydroxybutyrate, acetoacetate, free fatty acids, fructose, and oxygen were measured. Hepatic blood flow was also determined. At constant rates of splanchnic fructose extraction, an 82 per cent diminution of the arterial hepatic venous concentration difference of the ketones was observed but the arteriovenous difference of free fatty acis rose moderately. Since hepatic blood flow was only slightly increased (17 per cent) there was no doubt that total hepatic ketone body formation was reduced. The magnitude of this antiketogenic action became apparent from the continuous fall of the arterial ketone concentrations. Since splanchnic oxygen uptake rose 40 per cent, it is suggested that the antiketogenic effect of fructose was due not only to enhanced re-esterification but also to accelerated oxidation of free fatty acids.