Dietary Strontium and Calcium and Deposition of Sr 89 and Ca 45 in the Bones of Rats. ∗

Summary

Diets containing various levels of stable strontium and calcium and containing low and constant levels of Ca⁴⁵ and Sr⁸⁹ were fed to young rats during a 3 week period. The amounts of the 2 isotopes in the bones were measured. Addition of small amounts of stable Sr, sufficient to reduce the specific activity of the dietary Sr to one-fourth, did not decrease the deposition of radio-Sr and may have caused a slight increase in the deposition of both Ca⁴⁵ and Sr⁸⁹. Larger amounts of stable Sr were no more effective than calcium in reducing the amounts of the isotopes deposited in the bones.