Selective expression of a normal action of the 1,25-dihydroxyvitamin D3 receptor in human skin fibroblasts with hereditary severe defects in multiple actions of that receptor

J. Barsony, W. McKoy, D. A. DeGrange, U. A. Liberman, S. J. Marx

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

We evaluated three actions of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] in human skin fibroblasts to test for heterogeneity in hormone-response coupling. In fibroblasts from normal subjects the 1,25-(OH)2D3 concentrations for half-maximal effect (EC50) were: for mitogenic effect 0.0001-0.0005 nM, for antimitogenic effect 1 nM, and for induction of 25-OHD3 24-hydroxylase (24-OHase) 5 nM. To evaluate the effects of mutations presumed to be in the gene for the 1,25-(OH)2D3 receptor we examined cell lines representing four kindreds with hereditary resistance to 1,25-(OH)2D3 ('mutant' cell lines). In one mutant cell line all three 1,25-(OH)2D3 actions were severely abnormal. In one mutant cell line 24-OHase induction and mitogenic action were undetectable, but EC50 and maximal effect were normal for antimitogenic action of 1,25-(OH)2D3. In two mutant cell lines 24-OHase induction and antimitogenic actions were undetectable or severely impaired but mitogenic action was normal in EC50 and normal or increased in maximal effect. The mitogenic and antimitogenic actions in normal cells showed a similar profile of potency ratios for 1,25-(OH)2D3 and six analogues. Whenever a mutant cell showed a normal or even an abnormal mitogenic or antimitogenic effect of 1,25-(OH)2D3, these effects showed potency ratios similar to wild type, suggesting mediation by a similar 1,25-(OH)2D3 receptor. We conclude that three 1,25-(OH)2D3 actions show important differences in hormone response coupling indicated by differences in EC50 for 1,25-(OH)2D3 and by different consequences of receptor mutations.

Original languageEnglish
Pages (from-to)2093-2101
Number of pages9
JournalJournal of Clinical Investigation
Volume83
Issue number6
DOIs
StatePublished - 1989
Externally publishedYes

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