Abstract of the 68th Meeting (Spring Meeting) 6–9 March 1990, Heidelberg

Glucose, Lactate, and Ketone Body Utilization by Human Mammary Carcinomas in Vivo

Uncontrolled growth, one of the fundamental properties of malignant tumors, requires a great supply of energy. This energy can be derived from the use of a variety of substrates. Besides glucose oxidation and glucose breakdown to lactic acid, the turnover of endogeneous substrates such as amino acids, free fatty acids and ketone bodies is well documented in vitro. However, under in vivo conditions, only glucose utilization has been investigated in detail, using tumor isotransplants in rodents. For human tumors, only scarce data is available, derived mainly from clinical observations rather than from systematic studies.

Biokinetisches Verhalten und Stoffwechselwirkungen von Fructose bei hochdosierter Dauerinfusion an der Ratte

The steady-state blood level of fructose during 24 hours intravenous infusion in response to different doses follows saturation kinetics. Even after toxic doses of 1.5 g/kg/h no depletion of liver adenine nucleotides can be observed after 24 hours. In the kidneys, however, ATP, ADP and total adenine nucleotides were decreased after a dose of 1.5 g/kg/h of fructose. The blood glucose increased continuously at infusion rates of 1.5 g/kg/h. Inorganic phosphate in the blood increased at doses of 1.0 and 1.5 g/kg/h. The weight of the kidneys increased, presumably through water uptake. Urinary secretion was drastically reduced at doses above 1.0 g/kg/h. An appreciable activity of ketohexokinase c…

Dynamics of ketone body metabolism in diabetic rats.

Steady state blood levels of ketone bodies during infusions of acetoacetate at various rates have been compared in healthy and diabetic rats. The characteristics of the metabolic elimination of ketone bodies from the blood are completely changed in diabetic rats. Whereas steady state levels of ketone bodies increase linearly with the infusion rate in healthy rats, this increase is exponential in diabetic animals. This difference, which is due to an impaired metabolic elimination, becomes evident only above a dosage of 50 μmoles acetoacetate per kg per min. Chronic treatment with insulin for 4–6 days, but not acute insulin injection, restores the capacity of diabetic rats to metabolize keton…