Author
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Hunt, Curtiss |
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Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only Publication Acceptance Date: 4/18/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Moderate habitual exercise for older adults is considered important in the control of osteoporosis. Physiologic amounts of dietary boron (PDB) are known to affect growth plate morphology, bone mineral concentrations and circulating amounts of cholecalciferol metabolites. A study was initiated to ascertain whether PDB influences the changes in bone mineral concentrations induced by exercise training (ET). In a 2 x 2 factorially- arranged experiment, weanling rats (9 per group) were fed a ground corn- casein-corn oil based diet (vitamin- and mineral-adequate; 0.15 mg B/kg) supplemented with 0 or 1.14 mg B/kg. After 14 d, they remained sedentary or were placed in a treadmill and given incremental training (first d of ET, 33.6 m in 4 min; last d of ET, 353 m in 42 min) during the next 32 d (5d/week). At 67 d of age and after overnight fasting, PDB increased femur boron concentrations (0.043 vs 0.035 mmol/kg; p<0.03). In rats deprived of boron, ET had no effect on the femur concentrations of Ca (3.59 vs 3.66 mol/kg), P (2.27 vs 2.32 mol/kg), and Mg (0.108 vs 0.111 mol/kg). However, ET, concurrent with PDB, increased the femur concentrations of Ca (3.92 vs 3.47 mol/kg; p< 0.01), P (2.53 vs 2.21 mol/kg; p< 0.01), and Mg (0.124 vs 0.106 mol/kg; p< 0.001). Plasma 25- hydroxycholecalciferol concentrations were highest in the group receiving PDB and no ET (39.2 nmol/L). The findings suggest that boron is one natural food substance that allows bone to respond to the beneficial effects of moderate habitual exercise and does so by modulating vitamin D metabolism. |
