Ecdysteroids elicit a rapid Ca2+ flux leading to Akt activation and increased protein synthesis in skeletal muscle cells.

Phytoecdysteroids, structurally similar to insect molting hormones, produce a range of effects in mammals, including increasing growth and physical performance. In skeletal muscle cells, phytoecdysteroids increase protein synthesis. In this study we show that in a mouse skeletal muscle cell line, C(2)C(12), 20-hydroxyecdysone (20HE), a common phytoecdysteroid in both insects and plants, elicited a rapid elevation in intracellular calcium, followed by sustained Akt activation and increased protein synthesis. The effect was inhibited by a G-protein coupled receptor (GPCR) inhibitor, a phospholipase C (PLC) inhibitor, and a phosphoinositide kinase-3 (PI3K) inhibitor.