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Author Rajasree, S. ♦ Umashankar, P. R. ♦ Lal, A. V. ♦ Sarma, P. S. ♦ Kartha, C. C.
Source Sree Chitra Tirunal Institute for Medical Sciences & Technology
Content type Text
Publisher Life Sciences
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Medicine & health ♦ Human physiology
Subject Domain (in MeSH) Cell Physiological Phenomena ♦ Physiological Phenomena ♦ Musculoskeletal and Neural Physiological Phenomena ♦ Biological Sciences
Subject Keyword Metabolism
Abstract Several studies have demonstrated that excess of vitamin D-3 is toxic particularly to vascular tissues. A notable pathological feature is arterial calcification. The nature of the toxic metabolite in hypervitaminosis D and the pathogenesis of arterial calcification are not clearly understood. The present study was undertaken to explore whether arterial calcification is a sequel of increased calcium uptake by arterial smooth muscle mediated by up regulation of vitamin D receptor in the cells in response to elevated circulating levels of vitamin D-3 in serum. The experimental study was performed in 20 New Zealand white female rabbits aged 6 months. Animals in the test group were injected 10,000 IU of cholecalciferol intramuscularly twice a week for one month. Six control animals were given intra-muscular injections of plain cottonseed oil. Animals were sacrificed and aortas were examined for pathological lesions, 1,25-dihyroxyvitamin D-3 (1,25(OH)(2) D-3) receptor levels and Ca-45 uptake in smooth muscle cells. Serum samples collected at intervals were assayed for levels of 25-OH-D-3 and calcium. The results showed that in animals given injections of cholecalciferol, serum levels of 25-OH-D-3 Were elevated. In four of these animals calcification and aneurysmal changes were seen in the aorta. Histological lesions comprised of fragmentation of elastic fibers as well as extensive loss of elastic layers. 1,25(OH)(2) D-3 receptor levels were up regulated and Ca-45 uptake enhanced in aortas of animals which were given excessive vitamin D-3. The evidences gathered suggest that excess vitamin D is arteriotoxic and that the vitamin induces arterial calcification through up regulation of 1,25(OH)(2)D-3 receptor and increased calcium uptake in smooth muscle cells of the arteries. (C) 2002 Elsevier Science Inc. All rights reserved.
Education Level UG and PG
Learning Resource Type Article
Educational Framework Medical Council of India (MCI)
Journal LIFE SCIENCES
Volume Number 70
Issue Number 15
Page Count 12
Starting Page 1777
Ending Page 1788