Arterial-Hepatic Vein Glucose Differences in Normal and Diabetic Man after a Glucose Infusion at Rest and after Exercise

Abstract

The role of the liver in the elimination of infused glucose during recovery after exercise was studied in 5 normal and 4 juvenile diabetic males and the results compared with those of a resting experiment. The subjects exercised on the bicycle ergometer at a work rate requiring about 70% of their .ovrhdot.VO2max. Glucose (0.5 g/kg body wt) was infused as a single injection 15 min after the cessation of exercise. Arterial-hepatic vein (a-hv) glucose and lactate differences were measured repetitively both during exercise and throughout the 79 min recovery period. During exercise the a-hv glucose differences were negative and increased more than 6-fold in the diabetic subjects and more than 10-fold in the non-diabetic subjects. After the glucose infusion the a-hv glucose differences were still negative in the diabetic subjects, indicating a continued net release of glucose from the liver in spite of elevated arterial glucose concentrations. In non-diabetic subjects there was a small uptake of glucose, accounting for about 0.5% of the total glucose load given. The a-hv lactate differences were larger in the diabetic subject, indicating a greater dependence upon gluconeogenesis as compared with the non-diabetic subjects. The liver is of no importance in the diabetic subjects and of only slight importance in the non-diabetic subjects for the disposal of infused glucose during the initial hour of recovery after exercise.