title: Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet.
abstract: The role of vitamin D in curtailing the development of obesity and comorbidities such as the metabolic syndrome (MetS) and type 2 diabetes has received much attention recently. However, clinical trials have failed to conclusively demonstrate the benefits of vitamin D supplementation. In most studies, serum 25-hydroxyvitamin D [25(OH)D] decreases with increasing BMI above normal weight. These low 25(OH)D levels may also be a proxy for reduced exposure to sunlight-derived ultraviolet radiation (UVR). Here we investigate whether UVR and/or vitamin D supplementation modifies the development of obesity and type 2 diabetes in a murine model of obesity. Long-term suberythemal and erythemal UVR significantly suppressed weight gain, glucose intolerance, insulin resistance, nonalcoholic fatty liver disease measures; and serum levels of fasting insulin, glucose, and cholesterol in C57BL/6 male mice fed a high-fat diet. However, many of the benefits of UVR were not reproduced by vitamin D supplementation. In further mechanistic studies, skin induction of the UVR-induced mediator nitric oxide (NO) reproduced many of the effects of UVR. These studies suggest that UVR (sunlight exposure) may be an effective means of suppressing the development of obesity and MetS, through mechanisms that are independent of vitamin D but dependent on other UVR-induced mediators such as NO.
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Sian
authors.initials: S
authors.lastname: Geldenhuys
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Prue H
authors.initials: PH
authors.lastname: Hart
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Raelene
authors.initials: R
authors.lastname: Endersby
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Jacoby
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, U.K.
authors.forename: Martin
authors.initials: M
authors.lastname: Feelisch
authors.affiliation: University of Edinburgh, MRC Centre for Inflammation Research, Edinburgh, Scotland.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Weller
authors.affiliation: Laboratory for Metabolic Dysfunction, Harry Perkins Institute of Medical Research, Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Vance
authors.initials: V
authors.lastname: Matthews
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia shelley.gorman@telethonkids.org.au.
authors.forename: Shelley
authors.initials: S
authors.lastname: Gorman
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000528:radiation effects; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000209:etiology / Q000532:radiotherapy; D059305:Diet, High-Fat; D018149:Glucose Intolerance / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy; D007333:Insulin Resistance / Q000528:radiation effects; D008297:Male; D024821:Metabolic Syndrome / Q000188:drug therapy* / Q000209:etiology / Q000532:radiotherapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000378:metabolism; D009765:Obesity / Q000188:drug therapy / Q000209:etiology / Q000532:radiotherapy; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D014807:Vitamin D; D009569:Nitric Oxide; C104450:25-hydroxyvitamin D