The Acute Biochemical Response of the Starved Rabbit Liver in Situ to Glucose Infusion

Increasing the blood glucose levels from 88 to 400 mg/IOO ml in rabbit liver in situ during 5-min time intervals resulted in a decrease in the production of C02 from C-I of liver glucose together with a slight increase in the oxidation of C-6 of glucose; this was caused by a high glucose-induced decrease in the activity of the oxidative pentose phosphate pathway. Increasing the glucose concentrations also resulted in a threefold increase in the levels of palmitoyl- and stearoyl-CoA esters at a glucose load of 0·8 g; this is consistent with a specific feed-back inhibition of the production of NADPH by reactions of the oxidative pentose phosphate pathway by long-chain fatty acyl-CoAs. A decrease in plasma free fatty acids occurred when blood glucose levels were raised; this was associated with an increase in the concentration of free fatty acids in liver.