Résumé :
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Neuregulin was initially described as a neurotrophic factor involved in the formation of the neuromuscular junction in skeletal muscle. However, in recent years, neuregulin has been reported to be a myokine that exerts relevant effects on the regulation of muscle metabolism. Neuregulin has been recognized to stimulate glucose transport in a manner that is similar and additive to insulin. Given the relationship between insulin and neuregulin action in the regulation of muscle glucose uptake, studies focused on establishing whether defects in neuregulin action contribute to the development of the hyperglycaemia associated with the insulin resistance states that characterize the metabolic syndrome appear to be fundamental. Moreover, chronic effects of neuregulin resemble those of muscle training and its release is induced by the muscle contraction. Further studies are thus required to finely precise the contribution of neuregulin to muscle adaptation in response to training and also address the question whether the neuregulin-associated mechanisms involved in the regulation of glucose uptake provide a therapeutical target to ameliorate physiopathological alterations observed in insulin resistance states. Male Wistar rats were fed with a control diet or a high sucrose-high fat diet for 8 weeks. The rats were randomly divided into two groups, a sedentary control group and a trained group (treadmill running, 5 day/wk for 8 weeks). Intraperitoneal glucose tolerance tests were performed and expression of neuregulin and erbB receptors were assessed in gastrocnemius muscles. Significant insulin resistance and obesity were observed in high sucrose high fat diet rats. Endurance training reduced fat mass. Expression of neuregulin and erbB receptors were modulated by diet and endurance training. Neuregulin could contribute to muscle and metabolic alterations observed in insulin resistance states.
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