Impaired FAD-glycerophosphate dehydrogenase activity in islet and liver homogenates of fa/fa rats.
The mitochondrial FAD-linked enzyme glycerophosphate dehydrogenase plays a key role in the pancreatic B-cell glucose sensing device. In the present study, the activity of this enzyme was examined in islets of fa/fa rats in which inherited diabetes mellitus is associated with obesity, hyperinsulinism and severe insulin resistance. The specific activity of both FAD-linked glycerophosphate dehydrogenase and glutamate dehydrogenase were decreased in islet and liver homogenates prepared from fa/fa, as compared to Fa/Fa, rats, this coinciding with a low ratio between glutamateoxalacetate and glutamate-pyruvate transaminase activity in both islet and liver extracts, islet hyperplasia, hyperinsulinemia and hepatic steatosis in the hyperglycemic fa/fa rats. It is speculated that a low activity of FAD-linked glycerophosphate dehydrogenase in the pancreatic B-cell may participate to the perturbation of glucose homeostasis in fa/fa rats, like in other animal models of non-insulin-dependent diabetes mellitus.
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
J
J
Rasschaert
F
F
Malaisse-Lagae
A
A
Sener
V
V
Leclercq-Meyer
L
L
Herberg
W J
WJ
Malaisse
D000410:Alanine Transaminase / Q000032:analysis; D000818:Animals; D001219:Aspartate Aminotransferases / Q000032:analysis; D001786:Blood Glucose / Q000032:analysis; D002237:Carbohydrate Dehydrogenases / Q000172:deficiency*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology* / Q000235:genetics; D005260:Female; D006946:Hyperinsulinism / Q000201:enzymology* / Q000235:genetics; D007333:Insulin Resistance / Q000235:genetics; D007515:Islets of Langerhans / Q000201:enzymology*; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D008930:Mitochondria, Liver / Q000201:enzymology*; D009765:Obesity / Q000201:enzymology* / Q000235:genetics; D051381:Rats; D011922:Rats, Mutant Strains / Q000378:metabolism*
D001786:Blood Glucose; D002237:Carbohydrate Dehydrogenases; C056470:3-glycerophosphate dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase