Enzymatic, metabolic and secretory patterns in human islets of type 2 (non-insulin-dependent) diabetic patients.
Islets were isolated by automatic digestion from non-diabetic cadaveric organ donors and from Type 2 (non-insulin-dependent) diabetic subjects. The activity of FAD-glycerophosphate dehydrogenase, but not that of either glutamate dehydrogenase, glutamate-oxalacetate transaminase or glutamate-pyruvate transaminase, was lower in Type 2 diabetic patients than control subjects. Hexokinase, glucokinase and glutamate decarboxylase activities were also measured in islets from control subjects. The utilization of D-[5-3H]glucose, oxidation of D-[6-14C]glucose and release of insulin evoked by D-glucose were all lower in Type 2 diabetic patients than control subjects. The secretory response to the combination of L-leucine and L-glutamine appeared less severely affected. Islets from Type 2 diabetic patients may thus display enzymatic, metabolic and secretory anomalies similar to those often observed in animal models of Type 2 diabetes, including a deficiency of beta-cell FAD-linked glycerophosphate dehydrogenase, the key enzyme of the glycerol phosphate shuttle.
Fernandez-Alvarez
J
J
Endocrinology and Diabetes Unit, Hospital Clinic Barcelona, Spain.
Conget
I
I
Rasschaert
J
J
Sener
A
A
Gomis
R
R
Malaisse
W J
WJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000410:Alanine Transaminase / Q000378:metabolism; D001219:Aspartate Aminotransferases / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D005941:Glucokinase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D005968:Glutamate Decarboxylase / Q000378:metabolism; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D006019:Glycolysis; D006593:Hexokinase / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012016:Reference Values
D007328:Insulin; D005993:Glycerolphosphate Dehydrogenase; D005969:Glutamate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D006593:Hexokinase; D005941:Glucokinase; D005968:Glutamate Decarboxylase; D005947:Glucose