Linked Life Data

3509742

Source:http://linkedlifedata.com/resource/pubmed/id/3509742

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1988-11-14
pubmed:abstractText
The effects of three vitamin D3 metabolites, 25-hydroxyvitamin D3 (25-(OH)D3), 1 alpha,25-dihydroxyvitamin D3 (1 alpha, 25-(OH)2D3), and 24R,25-dihydroxyvitamin D3 (24R,25-(OH)2D3) on the activity of alkaline phosphatase (AP), a key enzyme involved in biomineralization, have been studied in primary cultures of chicken epiphyseal growth plate chondrocytes. Dosages of 1 alpha, 25-(OH)2D3 (10(-12) to 10(-7) M) caused a progressive, dosage- and time-dependent decrease in cellular AP levels, IC50 occurring at approximately 10(-12) M. In contrast, 24R,25-(OH)2D3 at 10(-13) to 10(-10) M stimulated cellular AP activity, half-maximal stimulation occurring at about 10(-13) M. At higher levels (10(-10) to 10(-7) M), 24R,25-(OH)2D3 caused progressive reduction in AP activity. Maximal effects of 24R,25-(OH)2D3 were evident 48 h after administration of the metabolite. 25-(OH)D3 initially (24 h) caused a weak, dosage-dependent decrease in cellular AP activity, but after 48-72 h, low levels (10(-13) to 10(-11) M) caused a dosage-dependent increase in AP activity. Higher levels of 25-(OH)D (greater than 10(-10) M) were clearly inhibitory to AP. These findings reveal that the AP activity of growth plate chondrocytes is exquisitely sensitive to both 1 alpha,25- and 24R,25-(OH)2D3 but the response to each is in opposite directions. The paradoxical response of the cells to 25-(OH)D3 can be explained if the metabolite is slowly metabolized by a 24-hydroxylase to 24R,25-(OH)2D3 leading to stimulation of cellular AP.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0884-0431
pubmed:author
pubmed:issnType
Print
pubmed:volume
1
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
489-95
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Effect of vitamin D metabolites on the expression of alkaline phosphatase activity by epiphyseal hypertrophic chondrocytes in primary cell culture.
pubmed:affiliation
Department of Chemistry, University of South Carolina, Columbia 29208.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.