MYF5 and obesity due to melanocortin 4 receptor deficiency: GABA increased phosphorylation of the mTOR-4EBP1 interactions and protein levels of myogenic differentiation transcription factors, including MyoD, myogenin, MEF-2, Myf5, and Myf6, in the skeletal muscle of HFD-fed aged mice, suggesting that GABA alleviates obesity- and age-induced sarcopenia by promoting muscle regeneration.