Regulation of adipose tissue and skeletal muscle substrate metabolism by the stomach-derived hormone, ghrelin

Abstract

Ghrelin is a stomach-derived hormone and a potent appetite stimulant. Ghrelin has recently harbored interest as a potential regulator of carbohydrate and lipid metabolism in skeletal muscle and adipose tissue; however, in vivo ghrelin administration is confounded by secondary effects. The assessment of the direct metabolic effects of acylated (AG) and unacylated (UnAG) ghrelin is a relatively new area of research. In isolated adipocytes and muscle, ghrelin has demonstrated antilipolytic effects. In muscle, ghrelin has been shown to acutely stimulate fat oxidation, which may protect the muscle from the insulin-desensitizing effects of high fatty acid concentrations. The effects of ghrelin directly on muscle glucose uptake are controversial. Whether ghrelin can be utilized therapeutically for conditions such as type 2 diabetes will depend on our better understanding of ghrelin's independent effects on muscle and adipose tissue metabolism, and whether this can predict ghrelin's effects when administered in vivo.