Alteration of anomeric preference of glucose-induced insulin secretion by glyceraldehyde.
Glucokinase activity in pancreatic islets was dose-dependently inactivated by D-glyceraldehyde, whereas islet hexokinase activity was not altered. In untreated islets, alpha-D-glucose stimulated insulin secretion more efficiently than beta-D-glucose at a glucose concentration of 10 mM. However, glyceraldehyde highly attenuated the insulin-secretory response of pancreatic islets to alpha-D-glucose compared with that to beta-D-glucose. Thus, there was apparently no anomeric preference of glucose-induced insulin secretion in glyceraldehyde-treated islets. Glyceraldehyde affected neither the alpha-preference of glucose phosphorylation by glucokinase nor the beta-preference of glucose phosphorylation by hexokinase. Our study suggests that defective discrimination of glucose anomers by glyceraldehyde-treated islets may be caused by inactivation of glucokinase.
Murata
T
T
Department of Clinical Biochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan.
Miwa
I
I
Okuda
J
J
D000818:Animals; D004789:Enzyme Activation; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005941:Glucokinase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D005985:Glyceraldehyde / Q000494:pharmacology*; D006593:Hexokinase / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007536:Isomerism; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008954:Models, Biological; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar
D007328:Insulin; D005985:Glyceraldehyde; D006593:Hexokinase; D005941:Glucokinase; D005947:Glucose