title: The roles of vitamin D in skeletal muscle: form, function, and metabolism.
abstract: Beyond its established role in bone and mineral homeostasis, there is emerging evidence that vitamin D exerts a range of effects in skeletal muscle. Reports of profound muscle weakness and changes in the muscle morphology of adults with vitamin D deficiency have long been described. These reports have been supplemented by numerous trials assessing the impact of vitamin D on muscle strength and mass and falls in predominantly elderly and deficient populations. At a basic level, animal models have confirmed that vitamin D deficiency and congenital aberrations in the vitamin D endocrine system may result in muscle weakness. To explain these effects, some molecular mechanisms by which vitamin D impacts on muscle cell differentiation, intracellular calcium handling, and genomic activity have been elucidated. There are also suggestions that vitamin D alters muscle metabolism, specifically its sensitivity to insulin, which is a pertinent feature in the pathophysiology of insulin resistance and type 2 diabetes. We will review the range of human clinical, animal, and cell studies that address the impact of vitamin D in skeletal muscle, and discuss the controversial issues. This is a vibrant field of research and one that continues to extend the frontiers of knowledge of vitamin D's broad functional repertoire.
authors.affiliation: Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales, Australia. c.girgis@garvan.org.au
authors.forename: Christian M
authors.initials: CM
authors.lastname: Girgis
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: Clifton-Bligh
authors.forename: Mark W
authors.initials: MW
authors.lastname: Hamrick
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Gunton
mesh_terms: D000328:Adult; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2; D004195:Disease Models, Animal; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D051379:Mice; D018345:Mice, Knockout; D009119:Muscle Contraction / Q000502:physiology; D018908:Muscle Weakness / Q000209:etiology / Q000473:pathology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D009135:Muscular Diseases / Q000209:etiology / Q000503:physiopathology; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D014807:Vitamin D / Q000502:physiology*; D014808:Vitamin D Deficiency / Q000150:complications / Q000473:pathology / Q000503:physiopathology
chemical_list: D007328:Insulin; D018167:Receptors, Calcitriol; D014807:Vitamin D; D002118:Calcium