Conclusion
These results suggest that β2-adrenergic receptor have direct effects in human skeletal muscle affecting fuel metabolism and net protein synthesis, effects that might be favourable for both type 2 diabetes and muscle wasting disorders.
Methods
Human cultured myotubes were exposed to terbutaline in various concentrations (0.01-30 μM) for 4 or 96 h. Thereafter uptake of [14C]deoxy-D-glucose, oxydation of [14C]glucose and [14C]oleic acid were measured. Incorporation of [14C]leucine, gene expression by qPCR and proteomics analyses by mass spectrometry by the STAGE-TIP method were performed after 96 h exposure to 1 and 10 μM of terbutaline.
Objective
In vivo studies have reported several beneficial metabolic effects of β-adrenergic receptor agonist administration in skeletal muscle, including increased glucose uptake, fatty acid metabolism, lipolysis and mitochondrial biogenesis. Although these effects have been widely studied in vivo, the in vitro data are limited to mouse and rat cell lines. Therefore, we sought to discover the effects of the β2-adrenergic receptor agonist terbutaline on metabolism and protein synthesis in human primary skeletal muscle cells.
Results
The results showed that 4 h treatment with terbutaline in concentrations up to 1 μM increased glucose uptake in human myotubes, but also decreased both glucose and oleic acid oxidation along with oleic acid uptake in concentrations of 10-30 μM. Moreover, administration of terbutaline for 96 h increased glucose uptake (in terbutaline concentrations up to 1 μM) and oxidation (1 μM), as well as oleic acid oxidation (0.1-30 μM), leucine incorporation into cellular protein (1-10 μM) and upregulated several pathways related to mitochondrial metabolism (1 μM). Data are available via ProteomeXchange with identifier PXD024063.