Linked Life Data

15877868

Source:http://linkedlifedata.com/resource/pubmed/id/15877868

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2005-5-9
pubmed:abstractText
The responses of renal vitamin D metabolism to its major stimuli alter with age. Previous studies showed that the increase in circulating 1,25-dihydroxyvitamin D (1,25(OH)2D3) as well as renal 25-hydroxyvitamin D3 1-alpha hydroxylase (1-OHase) activity in response to dietary Ca or P restriction reduced with age in rats. We hypothesized that the mechanism involved in increasing circulating 1,25(OH)2D3 in response to mineral deficiency alters with age. In the present study, we tested the hypothesis by studying the expression of genes involved in renal vitamin D metabolism (renal 1-OHase, 25-hydroxyvitamin D 24-hydroxylase (24-OHase) and vitamin D receptor (VDR)) in young (1-month-old) and adult (6-month-old) rats in response to low-phosphate diet (LPD). As expected, serum 1,25(OH)2D3 increased in both young and adult rats upon LPD treatment and the increase was much higher in younger rats. In young rats, LPD treatment decreased renal 24-OHase (days 1-7, P<0.01) and increased renal 1-OHase mRNA expression (days 1-5, P<0.01). LPD treatment failed to increase renal 1-OHase but did suppress 24-OHase mRNA expression (P<0.01) within 7 d of LPD treatment in adult rats. Renal expression of VDR mRNA decreased with age (P<0.001) and was suppressed by LPD treatment in both age groups (P<0.05). Feeding of adult rats with 10 d of LPD increased 1-OHase (P<0.05) and suppressed 24-OHase (P<0.001) as well as VDR (P<0.05) mRNA expression. These results indicate that the increase in serum 1,25(OH)2D3 level in adult rats during short-term LPD treatment is likely to be mediated by a decrease in metabolic clearance via the down-regulation of both renal 24-OHase and VDR expression. The induction of renal 1-OHase mRNA expression in adult rats requires longer duration of LPD treatment than in younger rats.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0007-1145
pubmed:author
pubmed:issnType
Print
pubmed:volume
93
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
299-307
pubmed:dateRevised
2008-8-16
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Age-related alteration of vitamin D metabolism in response to low-phosphate diet in rats.
pubmed:affiliation
Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PRC.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't