Effect of streptozotocin diabetes on the glycolytic flux and on fructose 2,6-bisphosphate levels in isolated rat enterocytes.
In epithelial cells isolated from rat small intestine and incubated in the presence of 1 mM glucose, streptozotocin-induced diabetes reduced, by 46 and 29%, respectively, the rates of both glucose utilization and L-lactate formation. These effects were accompanied by a significant decrease of enterocyte fructose 2,6-bisphosphate concentration (about 50%) and of the glycolytic flux through the reaction catalyzed by 6-phosphofructo 1-kinase. The diminution of enterocyte fructose 2,6-bisphosphate levels caused by diabetes occurred in spite of an increase of hexose 6-phosphate concentration, and was associated with a reduction in the amount of active form of 6-phosphofructo 2-kinase; total activity of this enzyme was not significantly modified. Diabetes also caused an acceleration in the rate of 3-O-methyl-D-(14C) glucose uptake and increased hexokinase activity in enterocytes. Lactate dehydrogenase, pyruvate kinase and 6-phosphofructo 1-kinase activities were not found to be significantly different in epithelial cells isolated from control or diabetic animals. Our results indicate that a reduction of the glycolytic flux in enterocytes could collaborate to increase intestinal glucose absorption in the diabetic state.
Rossi
I
I
Servicio de Gastroenterología, Clínica Puerta de Hierro, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
Sánchez-Arias
J A
JA
Felíu
J E
JE
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D005635:Fructosediphosphates / Q000378:metabolism*; D006019:Glycolysis; D006598:Hexosediphosphates / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism*; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism; D010732:Phosphofructokinase-1 / Q000378:metabolism; D025481:Phosphofructokinase-2; D010770:Phosphotransferases / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D005635:Fructosediphosphates; D006598:Hexosediphosphates; C027652:fructose 2,6-diphosphate; D007770:L-Lactate Dehydrogenase; D010770:Phosphotransferases; D025481:Phosphofructokinase-2; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase