D-glucose metabolism in cross-linked pancreatic islets.
D-glucose metabolism was investigated in pancreatic islets that underwent cross-linking of intracellular proteins by dimethyl suberimidate. Both the utilization of D-[5-3H]glucose and oxidation of D-[U-14C]glucose were much more severely affected at high (16.7 mM) than at low (2.8 mM) concentration of the hexose, when comparing cross-linked to control islets. The preferential stimulation of D-[U-14C]glucose oxidation relative to D-[5-3H]glucose utilization, resulting from an increase in hexose concentration, was not abolished, however, in cross-linked islets. Likewise, the activation of phosphofructokinase in glucose-stimulated islets did not appear to be impaired in cross-linked islets, the islet content in tritiated acidic metabolites generated from D-[5-3H]glucose failing to be increased in cross-linked islets. It is proposed, therefore, that the impaired responsiveness of cross-linked islets to a rise in D-glucose concentration might be attributable to an altered regulation of glucokinase, as possibly resulting from a missing interaction of the enzyme with GLUT-2.
Vanhoutte
C
C
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Malaisse-Lagae
F
F
Malaisse
W J
WJ
D000818:Animals; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D004120:Dimethyl Suberimidate / Q000737:chemistry; D005941:Glucokinase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D011506:Proteins / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction
D003432:Cross-Linking Reagents; D011506:Proteins; D004120:Dimethyl Suberimidate; D005941:Glucokinase; D005947:Glucose