title: [Bone and Nutrition. Vitamin D independent calcium absorption].
abstract: Vitamin D endocrine system is required for normal calcium and bone homeostasis. Trans-epithelial calcium absorption is initiated with calcium entry into the intestinal epithelial cells from luminal fluid through calcium permeable channels, and those expressions are strongly supported by vitamin D action. On the other hands, dietary treatment, mineral supplementation or restriction, successfully improves intestinal calcium absorption in global vitamin D receptor knock-out (VDR KO) mice, though vitamin D dependent active transport pathway is lacking. Dietary rescue of intestinal calcium absorption provided a positive calcium balance in this mouse model, and suggested that the major role of vitamin D function on calcium homeostasis was considered to be intestinal active absorption. To elucidate the entire process of intestinal calcium absorption, vitamin D independent calcium transport system was characterized into either trans-cellular or para-cellular process.
authors.affiliation: Nagasaki University Graduate School of Biomedical Sciences, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Masuyama
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D004967:Estrogens / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D016226:Phosphorus, Dietary / Q000494:pharmacology; D011374:Progesterone / Q000502:physiology; D018167:Receptors, Calcitriol / Q000502:physiology; D019108:Tight Junctions / Q000378:metabolism; D014807:Vitamin D / Q000494:pharmacology / Q000502:physiology*
chemical_list: D004967:Estrogens; D016226:Phosphorus, Dietary; D018167:Receptors, Calcitriol; D014807:Vitamin D; D011374:Progesterone; D002118:Calcium