ROLE OF LIVER IN DISPOSAL OF ORALLY ADMINISTERED 14C-GLUCOSE IN NORMAL RAT

6-14C-glucose (specific activity 6.0 μCi/g) was administered by oesophageal tube to fasted normal rats; the load was 1.5 g/kg. Rats were killed, in groups, at 0, 10, 20, 30, 60, 120 and 180 min after administration of the load, and the blood and liver sampled. Serum insulin and serum glucose reached a peak at 20 min. The radioactive serum glucose measured by the radioactivity in the dimedone derivatives of 6-C of glucose reached a peak at 60 min. At this time, 92% of the serum glucose originated from the load. Liver glycogen started to rise after 10-20 min, reaching a maximum at 120 min. The incorporation of 14C-glucose into liver glycogen paralleled the changes in total glycogen. It is suggested that during the first hour following an oral glucose load there is a reduction in the hepatic release of glucose, accompanied by an increase in hepatic glycogen synthesis. During the second hour there is a further marked increase in hepatic glycogen. Between 120 and 180 min there is a decrease in hepatic glycogen, and hepatic glucose release increases. The results emphasize the important role of the liver in the disposal of an oral glucose load. © 1969 Springer-Verlag.