Comparison between AICAR and exercise-induced stimulation of skeletal muscle AMP-K on fat/glucose metabolism in diabetes

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Background and Rationale: Exercise is important in the life of the diabetic. In well controlled diabetes, the rates of whole body sugar usage and energy production in skeletal muscle (SkM) in response to acute exercise are similar to non-diabetics. However in diabetics, little information is available as to how SkM processes sugar and produces energy during exercise. Insulin controls SkM sugar and energy processing in sedentary subjects. During exercise, these processes are controlled by non-insulin factors. The chemical catalyst AMP activated protein kinase (AMP-K), which has been investigated only in normal exercising rats, is an important alternative regulator of acute sugar processing and energy supply for exercising SkM. No studies of AMP-K activity are available in diabetes. Our studies will focus on i) how important is the stimulation of SkM AMP-K in diabetes to efficient SkM sugar processing and energy production; ii) if the benefits of exercise can be simulated by pharmacological stimulation of AMP-K in sedentary diabetic subjects. We aim to i) compare the metabolic effects of exercise vs pharmacological stimulation of AMP-K in normal and diabetic subjects; ii) define the molecular mechanisms which trigger the AMP-K metabolic responses; iii) determine if the circulating levels of insulin, blood sugar and-or blood fat influence the AMP-K metabolic responses. Likely Outcomes: pharmacological stimulation of AMP-K will improve SkM sugar metabolism, but less so in diabetes. The associated AMP-K stimulation of SkM fat metabolism may blunt the beneficial SkM sugar responses, particularly in diabetes. This information will be used in future drug developments for diabetics which aim to simulate the beneficial AMP-K metabolic effects of exercise.