It has long been recognised that vitamin D deficiency is associated with muscle weakness, which resolves with treatment of low vitamin D. However, the mechanisms behind this remain controversial, including the even whether the vitamin D receptor (VDR) itself is even expressed in muscle in adults.
Using whole-body vitamin D receptor null, and normal mice, tissue specific mice, and a validated model of vitamin D deficiency, we show that vitamin D is expressed in muscle in normal mice. The effects of abnormal vitamin D signalling in muscle will be discussed, and implications for therapy of muscle disorders.