Noninvasive assessment of exercise-related intramyocellular acetylcarnitine in euglycemia and hyperglycemia in patients with type 1 diabetes using 1H magnetic resonance spectroscopy: A randomized single-blind crossover study

Abstract

OBJECTIVE - Intramyocellular acetylcarnitine (IMAC) is involved in exercise-related fuel metabolism. It is not known whether levels of systemic glucose influence IMAC levels in type 1 diabetes. RESEARCH DESIGN AND METHODS - Seven male individuals with type 1 diabetes performed 120 min of aerobic exercise at 55-60% of VO2max randomly on two occasions (glucose clamped to 5 or 11 mmol/l, identical insulinemia). Before and after exercise, IMAC was detected by 1H magnetic resonance spectroscopy in musculus vastus intermedius. RESULTS - Postexercise levels of IMAC were significantly higher than pre-exercise values in euglycemia (4.30 ± 0.54 arbitrary units [a.u.], P < 0.001) and in hyperglycemia (2.44 ± 0.53 a.u., P = 0.01) and differed significantly according to glycemia (P < 0.01). The increase in exercise-related levels of IMAC was significantly higher in euglycemia (3.97±0.45 a.u.) than in hyperglycemia (1.71 ± 0.50 a.u.; P < 0.01). CONCLUSIONS - The increase in IMAC associated with moderate aerobic exercise in individuals with type 1 diabetes was significantly higher in euglycemia than in hyperglycemia. © 2011 by the American Diabetes Association.