title: Regulation of kidney calcium-binding protein in the bird (Gallus domesticus).
abstract: The possible involvement of plasma calcium and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in the regulation of the concentration of kidney calcium-binding protein (CaBP) was investigated. Chicks were fed diets varying in Ca2+ and P, with or without vitamin D. CaBP and 1,25(OH)2D3 were determined by competitive binding assays. A significant correlation between plasma and kidney 1,25(OH)2D3 was found, the linear regression equation of best-fit was plasma 1,25(OH)2D3 = 0.14 + 1.56 kidney 1,25(OH)2D3. In the vitamin D-fed chicks, kidney CaBP varied independently of the circulating or organ level of 1,25(OH)2D3 (P greater than 0.05), but was lower in the vitamin D-deficient than in the vitamin D-fed birds. A significant correlation was observed between kidney CaBP and plasma calcium (Cap). The regression equations were CaBP = Cap/(85.57-4.00 Cap) (R = 0.845) and CaBP = 0.0558 + 0.0404 Cap (R = 0.749), for vitamin D-treated and vitamin D-deficient chicks, respectively. The results suggest that the concentration of kidney CaBP is modulated by plasma calcium, but one or more of the vitamin D metabolites may be required for its synthesis.
authors.forename: J
authors.initials: J
authors.lastname: Rosenberg
authors.forename: S
authors.initials: S
authors.lastname: Hurwitz
authors.forename: A
authors.initials: A
authors.lastname: Bar
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002645:Chickens; D004032:Diet; D006706:Homeostasis; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D010710:Phosphates / Q000097:blood; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D014807:Vitamin D / Q000494:pharmacology
chemical_list: D002135:Calcium-Binding Proteins; D010710:Phosphates; D064030:S100 Calcium Binding Protein G; D014807:Vitamin D; D002117:Calcitriol; D002118:Calcium