Effect of dietary calcium deficiency during pregnancy on zinc mobilization in intact and parathyroidectomized rats.

The effects of dietary deprivation of calcium on teratogenicity of zinc deficiency were studied in both intact and parathyroidectomized rats. Intact females fed a diet deficient in both zinc and calcium during pregnancy had larger litters, fewer resorptions, and fewer malformed fetuses than did those fed a diet deficient in zinc alone, In addition, ash, zinc, and calcium contents of maternal bone were reduced. However, alleviation of the teratogenic effects of zinc deficiency by a diet simultaneously lacking calcium did not occur in parathyroidectomized rats. Furthermore, ash, zinc, and calcium concentrations of maternal femur were not decreased in these animals, indicating that they were unable to mobilize skeletal calcium or zinc. Thus, intact parathyroid glands are essential for alleviation of the teratogenic effects of zinc deficiency by dietary calcium deficiency. These results provide further evidence to support the hypothesis that conditions bringing about resorption of bone increase the availability of skeletal zinc.