Effect of high-dose glucocorticoid treatment on human brown adipose tissue activity: a randomised, double-blinded, placebo-controlled cross-over trial in healthy men

Glucocorticoids (GCs) are widely applied anti-inflammatory drugs that are associated with adverse metabolic effects including insulin resistance and weight gain. Previous research indicated that GCs may negatively impact brown adipose tissue (BAT) in rodents and humans. Here, we demonstrate that treatment of human volunteers with high doses of GCs increases resting energy expenditure (REE) but does not reduce BAT activity. In line with the physiological results, gene expression in human BAT was not significantly altered by GCs in vivo. However, the RNA-sequencing of skeletal muscle revealed that GCs increase the expression of enzymes involved in calcium cycling as well as the respiratory chain. Collectively, these data suggest that the raise of EE after GCs exposure is mediated by skeletal muscle rather than a change in BAT activity. Overall design: Randomized crossover trial