title: The avian as an animal model for the study of the vitamin D endocrine system.
abstract: This paper presents a summary of experimental studies which utilized the White Leghorn cockerel, Gallus domesticus, as a suitable avian model for a detailed analysis of the mode of action of the seco-steroid vitamin D. It is now apparent that there exists a complex endocrine system which coordinates the metabolism of the parent vitamin D into a family of over 30 metabolites; the principal metabolites are 1,25(OH)2D3 and 24R,25(OH)2D3, which together orchestrate the spectrum of biological responses attributable to vitamin D. Key advances in elucidation of the scope of vitamin D endocrine system include the tissue distribution of both its steroid receptor and its gene-induced product, a 28,000 dalton calcium binding protein, termed calbindin-D28k. To date no less than 23 tissues have been found to have specific 1,25(OH)2D3 receptors; of these at least 10 were identified in avian studies. Similarly, nine avian tissues have been found to express the vitamin D-induced calcium binding protein, calbindin-D28k. These observations collectively demonstrate both the broad scope of the vitamin D endocrine system and the appropriateness of using avians as valid models for vitamin D endocrine research which has applicability and validity for mammals, including man.
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside 92521.
authors.forename: A W
authors.initials: AW
authors.lastname: Norman
mesh_terms: D000818:Animals; D064092:Calbindin 1; D064026:Calbindins; D002645:Chickens / Q000502:physiology*; D004247:DNA / Q000378:metabolism; D006728:Hormones / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D015394:Molecular Structure; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000235:genetics; D013256:Steroids / Q000502:physiology; D014807:Vitamin D / Q000378:metabolism / Q000502:physiology*
chemical_list: C576498:CALB1 protein, human; D064092:Calbindin 1; D064026:Calbindins; D006728:Hormones; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D064030:S100 Calcium Binding Protein G; D013256:Steroids; D014807:Vitamin D; D004247:DNA