Effects of 1,25-dihydroxyvitamin D3 on colonic calcium transport in vitamin D-deficient and normal rats. 1984

M J Favus, and C B Langman

To determine whether prior vitamin D intake influences the intestinal calcium absorptive action of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], we measured in vitro the two unidirectional transepithelial fluxes of calcium across descending colon segments from rats fed either a vitamin D-deficient or normal diet and injected with either 10, 25, or 75 ng of 1,25(OH)2D3 or vehicle alone. Vitamin D deficiency abolished net calcium absorption [J net, -2 +/- 2 vs. 12 +/- 2 (SE) nmol X cm-2 X h-1, P less than 0.001], and 10 ng of 1,25(OH)2D3 raised J net to levels found in normal rats. Larger doses (25 and 75 ng) increased J net above levels in normal rats given the same dose. In normal rats only 75 ng of 1,25(OH)2D3 increased calcium J net above vehicle control values (12 +/- 2 vs. 38 +/- 4 nmol X cm-2 X h-1, P less than 0.001). Circulating 1,25(OH)2D3 measured by radioreceptor assay was well correlated with calcium transport. For each dose of 1,25(OH)2D3 higher serum 1,25(OH)2D3 levels were reached in vitamin D-deficient rats. Only the 75-ng dose increased circulating 1,25(OH)2D3 and colonic calcium transport in normal rats. Intravenous [3H]-1,25(OH)2D3 disappeared more rapidly from the circulation of normal rats, suggesting that accelerated metabolic degradative processes for 1,25(OH)2D3 may be present in normal but not in vitamin D-deficient rats and may account for the lack of a biological response to 1,25(OH)2D3 in normal animals.

UI MeSH Term Description Entries
D008297 Male Males
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D002117 Calcitriol The physiologically active form of vitamin D. It is formed primarily in the kidney by enzymatic hydroxylation of 25-hydroxycholecalciferol (CALCIFEDIOL). Its production is stimulated by low blood calcium levels and parathyroid hormone. Calcitriol increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid hormone increases bone resorption. 1 alpha,25-Dihydroxycholecalciferol,1 alpha,25-Dihydroxyvitamin D3,1, 25-(OH)2D3,1,25(OH)2D3,1,25-Dihydroxycholecalciferol,1,25-Dihydroxyvitamin D3,1 alpha, 25-dihydroxy-20-epi-Vitamin D3,1,25(OH)2-20epi-D3,1,25-dihydroxy-20-epi-Vitamin D3,20-epi-1alpha,25-dihydroxycholecaliferol,Bocatriol,Calcijex,Calcitriol KyraMed,Calcitriol-Nefro,Decostriol,MC-1288,MC1288,Osteotriol,Renatriol,Rocaltrol,Silkis,Sitriol,Soltriol,Tirocal,1 alpha,25 Dihydroxyvitamin D3,1,25 Dihydroxycholecalciferol,1,25 Dihydroxyvitamin D3,1,25 dihydroxy 20 epi Vitamin D3,Calcitriol Nefro,D3, 1 alpha,25-Dihydroxyvitamin,D3, 1,25-Dihydroxyvitamin,D3, 1,25-dihydroxy-20-epi-Vitamin,KyraMed, Calcitriol,MC 1288
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D003106 Colon The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON. Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D004553 Electric Conductivity The ability of a substrate to allow the passage of ELECTRONS. Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001692 Biological Transport The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments. Transport, Biological,Biologic Transport,Transport, Biologic
D014808 Vitamin D Deficiency A nutritional condition produced by a deficiency of VITAMIN D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as RICKETS in children and OSTEOMALACIA in adults. (From Cecil Textbook of Medicine, 19th ed, p1406) Deficiency, Vitamin D,Deficiencies, Vitamin D,Vitamin D Deficiencies
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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