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.

Renewed avenues through exercise muscle contractility and inflammatory status.

Physical inactivity leads to the accumulation of visceral fat and, consequently, to the activation of a network of inflammatory pathways which may promote development of insulin resistance, atherosclerosis, neurodegeneration, and tumour growth. These conditions belong to the "diseasome of physical inactivity". In contrast, the protective effect of regular exercise against diseases associated with chronic inflammation may to some extent be ascribed to an anti-inflammatory effect.

HMB supplementation: clinical and athletic performance-related effects and mechanisms of action.

Amino acids such as leucine and its metabolite α-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle.

Glucocorticoids: extensive physiological actions modulated through multiple mechanisms of gene regulation.

Glucocorticoid hormones are important regulators of several physiological processes. Despite having been initially named based on their role in glucose metabolism, glucocorticoids are also fundamental in the regulation of developmental, metabolic, and neurobiological processes, as well as several other biological functions. Due to their involvement in a diverse array of biological pathways, its wide spectrum of action, it is predicted that a wide range of genes may have their expression regulated by the activated glucocorticoid receptor (GR).