Turnover rate of blood glucose in diabetic KK mice

Metabolic rate constants for blood glucose turnover were estimated based on the decay of [U-14C, 6-3H]glucose injected intravenously in genetically diabetic KK mice. Comparison was made with the rate constants similarly obtained with non-diabetic and streptozotocin-induced diabetic ICR mice. Recycling of blood glucose via the Cori cycle, as estimated from the difference in the decay rate between 14C and 3H, was more active in KK mice than in non-diabetic and diabetic ICR mice. The Cori cycle activity was reduced by beta-adrenergic blockade in KK mice and was enhanced by alpha-blockade in ICR mice. It is concluded that predominance of beta-adrenergic functions in KK mice is responsible for activation of the Cori cycle as one of the mechanisms for metabolic resistance to endogenous insulin.