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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #184928
Title: ISOLATION AND IDENTIFICATION OF 3-EPI VITAMIN D3: A NOVEL METABOLITE OF VITAMIN D3

Author
item WANG, G - BROWN UNIVERSITY
item PALMORE, G - BROWN UNIVERSITY
item CEAILLES, C - NORTHEASTERN UNIV
item VOUROS, P - NORTHEASTERN UNIV
item RAY, R - BOSTON UNIVERSITY
item Horst, Ronald
item REDDY, G - BROWN UNIVERSITY

Submitted to: American Society for Bone and Mineral Research
Publication Type: Abstract Only
Publication Acceptance Date: 9/23/2005
Publication Date: 9/23/2005
Citation: Wang, G., Palmore, G.T., Ceailles, C., Vouros, P., Ray, R., Horst, R.L., Reddy, G.S. 2005. Isolation and identification of 3-epi Vitamin D3: A novel metabolite of Vitamin D3 [abstract]. American Society for Bone and Mineral Research. Available: http://www.asbmr.org/meeting/abstracts.cfm.

Interpretive Summary:

Technical Abstract: Since our original demonstration of the metabolism of 1 alpha,25(OH)2D3 into 1 alpha,25(OH)2-3-epi-D3 in human keratinocytes, there have been several reports indicating that epimerization of the 3 hydroxyl group of vitamin D compounds is a common metabolic process. Recent studies reported that metabolism of 25OHD3 and 24, 25(OH)2D3 into their respective C-3 epimers, indicating that the presence of 1 alpha hydroxyl group is not necessary for the 3-epimerization of vitamin D compounds. In our most recent study, we also reported the metabolism of 1 alphaOHD3, a non 25-hydroxylated vitamin D3 compound into its 3 epimer. From these studies, it became obvious that the presence of neither 1 alpha hydroxyl group nor 25 hydroxyl group is required for C-3-epimerization of vitamin D compounds, and that vitamin D3 itself can be 3 epimerized. To provide direct proof of the metabolism of vitamin D3 into its C-3 epimer we studied the metabolism of vitamin D3 in the human hepatocellular carcinoma (Hep G2) cell line, which is known to express the C-3 epimerization pathway. We noted the conversion of vitamin D3 into a new metabolite, the identity of which was established to be 3 epi vitamin D3 by its comigration with synthetic 3-epi vitamin D3 standard in two different HPLC systems and GC/MS analysis. Furthermore, we also isolated 3 epi vitamin D3 from the serum of vitamin D3 intoxicated rats. Thus for the first time we show that vitamin D3 itself can be metabolized into its C-3 epimer both in vitro and in vivo.