HMB has been shown to stimulate the proliferation, differentiation, and fusion of human myosatellite cells "in vitro", which potentially increases the regenerative capacity of skeletal muscle, by increasing the protein expression of certain myogenic regulatory factors (e.g., myoD and myogenin) and gene transcription factors (e.g., MEF2). HMB-induced human myosatellite cell proliferation "in vitro" is mediated through the phosphorylation of the mitogen-activated protein kinases ERK1 and ERK2. HMB-induced human myosatellite differentiation and accelerated fusion of myosatellite cells into muscle tissue "in vitro" is mediated through the phosphorylation of Akt, a serine/threonine-specific protein kinase.