Effect of intraperitoneal injection of glucose on glucose oxidation and energy expenditure in the mdx mouse model of Duchenne muscular dystrophy

Previous studies suggesting that glucose metabolism could be impaired in the skeletal muscles of the mdx mouse led us to study the metabolic response to i.p. injection of either glucose or glucose and insulin in the free-moving mdx mouse. In the first study, changes in blood glucose and plasma insulin levels were measured in mice with chronic venous cannulae. In the second study, the thermogenic response to glucose and the changes induced on glucose oxidation (Gox) and lipid oxidation (Lox) were assessed by indirect calorimetry. The experiments showed that insulin response, as well as whole body glucose uptake, were normal in mdx mice. Addition of exogenous insulin abolished the increase in blood glucose level similarly in mdx and control mice. The thermogenic response to glucose was identical in mdx and control mice but, when insulin was injected with glucose, it increased significantly in mdx mice. Exogenous glucose increased G ox less and decreased L ox less in mdx than in control mice. Addition of exogenous insulin reduced the difference between mdx and control mice but affected G ox and L ox less in mdx than in control mice.