Date of Award:

12-2011

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Ilka Nemere

Committee

Ilka Nemere

Committee

Korry Hintze

Committee

Robert E. Ward

Abstract

This research studied the effects of the two isomers of 24,25(OH)2D3 on phosphate absorption in vivo to increase our understanding of the effects of 24,25(OH)2D3 on phosphate transport in vivo, and its two isomers. The current work demonstrates that 24R,25(OH)2D3 is capable of decreasing phosphate absorption after a 1h injection in vivo and 24S,25(OH)2D3 can increase phosphate absorption after a 5h injection, but this stimulation disappears at time points after 5h.

Since 24,25(OH)2D3 is made in vitamin D-replete animals, the observation that 24R,25(OH)2D3 decreases phosphate absorption suggests that over supplementation of feeds with vitamin D may be counterproductive. Whether or not the unexpected observation that 24S,25(OH)2D3 briefly stimulates absorption off sets this inhibition is unknown. It is also likely that a lower level of supplementation with vitamin D would be adequate for bone growth. Thus, appropriate levels of vitamin D supplementation may result in more efficient utilization of phosphate in the diet, which would provide the benefits of reducing feed costs and reducing phosphorous excretion, thereby contributing to the sustainability of agriculture in the United States. Finally, these studies have implications for bone health in all animals, including humans to prevent rickets in children and osteoporosis in adults.

Checksum

bc19dd04c08398496f46d31b29bb1949

Comments

Publication made available electronically January 24, 2012.

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