Premium
High dose C‐3 alpha epimer of 25‐hydroxyvitamin D over 8 weeks reduces cortical mineral density of lumbar vertebra in weanling rats (828.2)
Author(s) -
DjekicIvankovic Marija,
Mak Ivy,
Wang Krystyna,
Lavery Paula,
Agellon Sherry,
Weiler Hope
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.828.2
Subject(s) - weanling , endocrinology , medicine , bone mineral , parathyroid hormone , vitamin d and neurology , calcitriol , bone density , osteoporosis , cortical bone , chemistry , calcium , anatomy
C‐3 alpha epimer (EPI) of 25‐hydroxyvitamin D (25(OH)D) is elevated in infancy. Short‐term treatment with the EPI of calcitriol reduces parathyroid hormone (PTH) in rats. This study tested the effect of EPI on growth, bone biomarkers and volumetric bone mineral density (vBMD). Weanling rats (4 wk; n=6 male; n=6 female/diet) were randomized to receive AIN‐93G diets modified in vitamin D for 8 wk: control AIN‐93G (C‐1: 25 µg vitamin D3/g diet), control 25(OH)D (C‐2: 12.5 µg 25(OH)D/g diet), level one EPI (EPI‐1: 12.5 µg EPI/g diet) or level two EPI (EPI‐2: 25 µg EPI/g diet). Measures were weight and biomarkers at 0, 4 and 8 wk and in vivo lumbar vertebra 3 vBMD using microcomputed tomography (LCT‐200, Aloka) at 0 and 8 wk. Differences among groups were tested using ANOVA, Tukey’s post hoc test and P<0.05. No differences in vitamin D status as measured using LC‐MS/MS were observed at baseline. Average serum EPI (range ng/ml) at 8 wk was C‐1: 4 (0‐12), C‐2: 2 (0‐7), EPI‐1: 49 (27‐78) and EPI‐2: 98 (41‐173). Weight, ionized Ca and C‐telopeptides of Type 1 collagen were not affected by diet. PTH was lowest in EPI‐2 vs all groups at wk 4; and lower in EPI‐1 and EPI‐2 vs C‐2 at wk 8. Cortical vBMD was lowest in EPI‐2 vs all other groups at wk 8; but not trabecular or total vBMD. These data suggest that pharmacological concentrations of EPI reduce PTH and cortical density during rapid growth. Grant Funding Source : Supported by NSERC and Dairy Farmers of Canada