EFFECTS OF GERMANIUM AND SILICON ON BONE MINERALIZATION

The chemical properties of Ge are similar to Si, This study investigat ed whether Ge can substitute for, or is antagonistic to, Si in bone fo rmation. Sixty male weanling Sprague-Dawley rats were randomly assigne d to treatment groups of 12 and 6 in a 2 x 4 factorially arranged expe riment. The independent variables were, per gram fresh diet, Si (as so dium metasilicate) at 0 or 25 mu g and Ge (as sodium germanate) at 0, 5, 30, or 60 mu g. Results confirmed that Ge does not enhance Si depri vation and provided evidence that Ge apparently can replace Si in func tions that influence bone composition. When Si was lacking in the diet , calcium and magnesium concentrations of the femur were decreased; th is was reversed by feeding either Ge and/or Si. Similar effects were f ound for zinc, sodium, iron, manganese, and potassium of vertebra. The re were some responses to Si deprivation that Ge could not reverse; Ge did not increase femur copper, sodium, or phosphorus or decrease moly bdenum of vertebra, effects that were evoked by Si supplementation Add itionally, some findings suggested that 60 mu g Ge/g diet could be a t oxic intake for the rat. On the other hand, some responses induced by Ge indicate that this element may be acting physiologically other than as a substitute for Si. Germanium itself affected bone composition. G ermanium supplementation decreased Si and molybdenum in the femur and increased DNA in tibia. Regardless of the amount of Si fed, animals fe d 30 mu g Ge/g diet had increased tibial DNA compared to animals fed 0 or 60 mu g Ge; however, tibial DNA of animals fed 30 mu g Ge was not statistically different from those animals fed 5 mu g Ge. Thus, Ge may be of nutritional importance.