Overexpression of either liver type or pancreatic beta cell type glucokinase via recombinant adenovirus enhances glucose oxidation in isolated rat hepatocytes.
To elucidate a role of glucokinase in hepatic glucose metabolism, we overexpressed hexokinase I (HKI), liver type glucokinase (LGK), or beta cell type glucokinase (beta GK) in primary rat hepatocytes using a recombinant adenovirus vector system. Overexpression of HKI and LGK induced a 34- and 25-fold increase, respectively, in glucose phosphorylation activity measured in cell homogenates. While HKI overexpression induced only a 1.3-fold increase in glucose oxidation, LGK overexpression increased glucose oxidation by 2.9-fold. Overexpression of beta GK had essentially the same effect as LGK. The results indicate that glucokinase does indeed regulate the rate of hepatic glucose oxidation and that the liver-specific sequence of this enzyme is not essential for this function.
Takeuchi
H
H
Third Department of Internal Medicine, Yamaguchi University School of Medicine, Japan.
Inoue
Y
Y
Ishihara
H
H
Oka
Y
Y
D000260:Adenoviruses, Human / Q000235:genetics; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D005941:Glucokinase / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006593:Hexokinase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics
D011993:Recombinant Fusion Proteins; D006593:Hexokinase; D005941:Glucokinase; D005947:Glucose