|Seaborn, Carol - UNIVERSITY OF WISCONSIN|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2000
Publication Date: March 7, 2001
Citation: Seaborn, C.D., Nielsen, F.H. 2001. Cysteine, silicon, and their interaction affect bone composition in the rat [abstract]. The Federation of American Societies for Experimental Biology Journal. 15:A972. Technical Abstract: Because several bone-remodeling proteins are rich in cysteine, we performed a study to ascertain whether cysteine (Cys) would affect bone composition in animals deprived of silicon (Si). Male weanling Sprague- Dawley rats were randomly assigned to treatment groups of nine in a 2 X 4 factorially arranged experiment. The rats were fed for nine weeks a basal casein-ground corn-corn oil diet containing 1.9 ug Si, 1.7 mg Cys, and 4.7 mg methionine per g. The independent treatment variables, per g fresh diet, were supplemental Si (as sodium metasilicate) at 0 and 35 ug and Cys at 0 and 12 mg. Silicon deprivation decreased the concentration of hydroxyproline in femur. Supplemental Cys markedly increased the zinc concentration in vertebra and tibia; dietary Si did not influence this effect. Supplemental Cys also increased the tibial concentrations of calcium (Ca), phosphorus (P), magnesium and molybdenum; dietary Si did not significantly affect these increases. In the vertebra, on the other hand, dietary Si influenced the effect of Cys on mineral composition. Vertebra Ca and P were markedly increased by supplemental Cys when dietary Si was inadequate, but not when it was adequate. Supplemental Cys increased vertebral concentrations of manganese and copper when dietary Si was adequate, but decreased these concentrations when dietary Si was inadequate. The findings suggest that Si nutriture has more impact on trabecular-rich bone than in cortical-rich bone. Moreover, high dietary Cys apparently enhances changes induced by Si deprivation in trabecular- rich bone.