Modulation of insulin action by dietary proteins and amino acids: role of the mammalian target of rapamycin nutrient sensing pathway

Abstract

An increasing number of studies point towards an important role of dietary proteins and amino acids in the modulation of insulin action in peripheral tissues. The purpose of this review is to discuss how these nutrients affect insulin sensitivity and the potential mechanism by which they exert their action. Increased plasma amino acid availability in both animals and humans has been shown to cause enhanced translation initiation and protein synthesis and the inhibition of insulin-stimulated glucose transport in skeletal muscle. Moreover, dietary interventions in animals fed proteins from various sources resulted in drastically different outcomes in terms of glucose metabolism and insulin signaling in skeletal muscles. Finally, amino acids, particularly leucine, were shown to modulate insulin action by specifically activating the mammalian target of rapamycin nutrient sensing pathway. Dietary proteins and amino acids are important modulators of glucose metabolism and insulin signaling via their ability, at least partly, to modulate the mammalian target of rapamycin pathway.