Dose and latency effects of leucine supplementation in modulating glucose homeostasis: opposite effects in healthy and glucocorticoid-induced insulin-resistance states.
Dexamethasone (DEXA) is a potent immunosupressant and anti-inflammatory agent whose main side effects are muscle atrophy and insulin resistance in skeletal muscles. In this context, leucine supplementation may represent a way to limit the DEXA side effects. In this study, we have investigated the effects of a low and a high dose of leucine supplementation (via a bolus) on glucose homeostasis, muscle mass and muscle strength in energy-restricted and DEXA-treated rats. Since the leucine response may also be linked to the administration of this amino acid, we performed a second set of experiments with leucine given in bolus (via gavage) versus leucine given via drinking water. Leucine supplementation was found to produce positive effects (e.g., reduced insulin levels) only when administrated in low dosage, both via the bolus or via drinking water. However, under DEXA treatment, leucine administration was found to significantly influence this response, since leucine supplementation via drinking water clearly induced a diabetic state, whereas the same effect was not observed when supplied via the gavage.
Laboratory of Applied Nutrition and Metabolism, School of Physical Education and Sports, University of Sao Paulo, Sao Paulo, Brazil. neloz@ig.com.br
Nelo Eidy
NE
Zanchi
Lucas
L
Guimarães-Ferreira
Mário Alves
MA
de Siqueira-Filho
Vitor
V
Felitti
Humberto
H
Nicastro
Carlos
C
Bueno
Fábio Santos
FS
Lira
Marshall Alan
MA
Naimo
Patrícia
P
Campos-Ferraz
Maria Tereza
MT
Nunes
Marília
M
Seelaender
Carla Roberta
CR
de Oliveira Carvalho
François
F
Blachier
Antonio Herbert
AH
Lancha
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003907:Dexamethasone / Q000009:adverse effects*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes; D005938:Glucocorticoids / Q000009:adverse effects*; D006706:Homeostasis / Q000187:drug effects; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D007930:Leucine / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000139:chemically induced / Q000188:drug therapy; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D005938:Glucocorticoids; D007328:Insulin; D003907:Dexamethasone; D007930:Leucine