The possible role of leucine in modulating glucose homeostasis under distinct catabolic conditions.
Branched-chain amino acids (BCAA) (especially leucine) have been shown to activate protein synthesis pathways, decrease proteolysis and increase insulin sensitivity. Furthermore, it appears that leucine can be used as a nutritional therapy to avoid sarcopenia and skeletal muscle atrophy due to immobilization or glucocorticoid treatment. However, it is of note that all of these conditions are related to insulin resistance to varying degrees and affect different tissues, particularly skeletal muscle. Additionally, evidence from recent studies demonstrate that a combination of protein containing high levels of leucine with nutrients containing saturated fatty acids or an excess of leucine are capable of inducing insulin resistance. From this discussion, a few major questions arise. First, what is the role of a combination of macronutrients in inducing insulin resistance? Second, in insulin resistance, does leucine supplementation follow the same path observed under healthy conditions? Finally, what are the dose-dependent outcome and the latency of leucine effect under such conditions? The present article discusses these questions based on data from the literature and experiments performed by our group.
Department of Physiology and Biophysics, University of São Paulo, São Paulo, Brazil. neloz@ig.com.br
Nelo Eidy
NE
Zanchi
Lucas
L
Guimarães-Ferreira
Mário Alves
MA
Siqueira-Filho
João Paulo
JP
Gabriel Camporez
Humberto
H
Nicastro
Daniela Fojo
DF
Seixas Chaves
Patrícia
P
Campos-Ferraz
Antonio Herbert
AH
Lancha
Carla Roberta
CR
de Oliveira Carvalho
D003907:Dexamethasone / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D007930:Leucine / Q000378:metabolism*; D008962:Models, Theoretical
D004044:Dietary Proteins; D003907:Dexamethasone; D007930:Leucine; D005947:Glucose