Skeletal response to dietary calcium in a rat model simulating weightlessness.

摘要: Unweighting the hindlimbs of a rat by tail suspension leads to decrease in bone unweighted hindlimbs, but not normally weighted forelimbs. We evaluated whether increments dietary calcium could prevent this. Growing rats were fed diets ranging content from 0.1% 2.4%. After suspended for two weeks, we found no differences between and control animals same diet with respect transport or serum levels calcium, phosphorus, 1,25-dihydroxyvitamin D, parathyroid hormone. In both groups, increasing reduced active intestinal D levels. The tibia lumbar vertebra (but humerus) was compared diet. However, increased all bones animals. formation rate at tibiofibular junction (measured double-label tetracycline) controls altered calcium. marrow area tibia, an indication resorption, did differ equally groups when increased. Our data suggest that deleterious effects skeletal unweighting on cannot be explained changes calciotropic hormones are reversed can increase even limbs, decreasing resorption.