Streptozotocin-induced suppression of FAD-linked glycerophosphate dehydrogenase in pancreatic islets of adult rats.

Injection of streptozotocin (30-40 mg/kg body weight) to adult rats caused within 4-6 days a sizeable decrease in the activity of FAD-linked glycerophosphate dehydrogenase in pancreatic islets, with little change in either glutamate dehydrogenase or 2-oxoglutarate dehydrogenase activity. The severity of the enzymatic defect was related to that of the diabetic state, although a decreased enzymic activity was also observed in islets from virtually normoglycemic animals examined 2-3 weeks after streptozotocin injection. The administration of nicotinamide prior to that of streptozotocin prevented the change in enzymic activity. It is proposed that the enzymatic defect, rather than being attributable to a genomic effect of streptozotocin, may reflect the preferential impairment of a subpopulation of pancreatic B-cells.