The presence of vitamin D receptors (VDRs) in the brain suggest that vitamin D had functions in this organ and accumulating data have provide evidence that this is indeed the case. Recently, it has been recognized that vitamin D behaves as a neuroactive compound (neurosteroid) largely implicated in the control of brain homeostasis. Likewise, the neuroprotective effects of vitamin D, achieved by its action levels of nerve growth factors in the treatment of neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). Recent studies on VDR gene knockout mice revealed that VDR also regulates behavioural characterization and differentiation of skeletal muscle. Thus, vitamin D appears to regulate development and homeostasis of the nervous system and skeletal muscle.