Glucose regulation of hepatic gluconeogenesis

Abstract

Isolated livers from fasted rats were perfused with a medium containing either 0, 150, or 300 mg/100 ml glucose [GLU] in order to study the effect of perfusate GLU concentration on gluconeogenesis from alanine-14c Gluconeogenesis, as reflected by the sum of alanine-C incorporation into perfusate GLU and glycogen [GLY] was greatest in the livers perfused with a GLU-free medium. Net GLU release into the perfusate was also greater in these livers wnile net GLY synthesis and GLU utilization were greatest in the livers with 300 mg/ 100 ml GLU in their initial medium. The specific activity of GLY GLU was 3- to 4-fold that of perfusate GLU in both livers with 150 mg/100 ml and 300 mg/100 ml GLU in their initial medium. Net amino acid utilization and urea production were both decreased in the liver perfused with higher GLU concentrations. These findings indicate that hepatic carbohydrate and ammo acid metabolism can be significantly affected by changes in GLU concentration even in the absence of hormonal alterations.