title: Oral intake of 7-dehydrocholesterol increases vitamin D3concentrations in the liver and kidney.
abstract: Due to the high prevalence of vitamin D deficiency, strategies are needed to improve vitamin D status. Food components can affect vitamin D metabolism and have to be considered when estimating the efficacy of vitamin D supplements. 7-dehydrocholesterol (7-DHC) occurs naturally in food, but its impact on vitamin D metabolism has not yet been examined.
  
  
  
  Three groups of male C57BL/6 mice (n=12 per group) were placed on a diet that contained 0, 2.5 or 5mg 7-DHC per kg diet over a period of 6 weeks. Vitamin D and other sterols in the serum, skin, liver and kidney were quantified by LC-MS/MS. The relative mRNA abundance of hepatic genes encoding vitamin D hydroxylation enzymes and transporters was analyzed by real-time RT-PCR.
  
  
  
  We found a substantial dose-dependent increase of non-hydroxylated vitamin D3in the liver and kidney of mice fed a diet containing 7-DHC. The vitamin D3content in the liver was 2.80±0.61pmol/g, 7.34±4.28pmol/g and 12.9±3.58pmol/g in groups that received 0, 2.5 and 5mg/kg 7-DHC, respectively. In the kidney, the vitamin D3content of these groups was 1.78±1.17pmol/g, 3.55±1.06 and 6.36±2.29pmol/g, respectively. The serum and tissue concentrations of 25-hydroxyvitamin D3(25(OH)D3) remained unaffected by 7-DHC. The relative mRNA data provided no plausible mechanism for the observed effects of 7-DHC on vitamin D3. All groups of mice had similar concentrations of cholesterol, desmosterol and 7-DHC in their serum and tissues.
  
  
  
  The current findings provide the first evidence that dietary 7-DHC seems to affect vitamin D metabolism. The underlying mechanism remains elusive and needs further investigation.
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany. Electronic address: julia.kuehn@landw.uni-halle.de.
authors.forename: Julia
authors.initials: J
authors.lastname: Kühn
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany. Electronic address: frank.hirche@landw.uni-halle.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Hirche
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany. Electronic address: stefanie.geissler@izi.fraunhofer.de.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Geissler
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany. Electronic address: gabriele.stangl@landw.uni-halle.de.
authors.forename: Gabriele I
authors.initials: GI
authors.lastname: Stangl
mesh_terms: D000284:Administration, Oral; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002112:Calcifediol / Q000032:analysis / Q000097:blood / Q000378:metabolism; D002762:Cholecalciferol / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D002784:Cholesterol / Q000032:analysis / Q000097:blood / Q000378:metabolism; D003684:Dehydrocholesterols / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements / Q000032:analysis; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D000072664:Provitamins / Q000008:administration & dosage / Q000494:pharmacology*; D014280:Triglycerides / Q000032:analysis / Q000097:blood / Q000378:metabolism
chemical_list: D003684:Dehydrocholesterols; D000072664:Provitamins; D014280:Triglycerides; D002762:Cholecalciferol; D002784:Cholesterol; C016705:7-dehydrocholesterol; D002112:Calcifediol
keywords: Dietary 7-dehydrocholesterol; Kidney; Liver; Mice; Vitamin D