Strontium-calcium interrelationships in the growing rat

¹ Biology Laboratory, Hanford Laboratories, General Electric Company, Richland, Washington

The comparative metabolic behavior of strontium and calcium was studied in growing, female rats exposed either continuously or to single doses of Sr⁹⁰ and Ca⁴⁵ while on diets of various total calcium contents. At weaning the discrimination against ingested Sr⁹⁰ relative to Ca⁴⁵ was markedly less than that previously observed in mature rats. This discrimination increased and approached the levels observed in mature animals, while growth and Ca⁴⁵ deposition was still proceeding at a rapid rate. The effect of a fourfold increase in dietary calcium (from 0.5 to 2.0%) over a 200-day feeding period was a twofold reduction in the steady-state level of Sr⁹⁰ in bone. As previously shown in mature rats, the retention (as opposed to absorption) of a single dose of Sr⁹⁰ was relatively unaffected by dietary calcium level, while that of Ca⁴⁵ varied from almost total retention on a 0.1% calcium diet to retention on a 2.0% calcium diet which was similar to that observed for Sr⁹⁰ on all diets.

Key Words: bone metabolism • strontium metabolism • calcium metabolism • nutritional effects on strontium metabolism • radioisotope hazards • fallout hazards • discrimination between calcium and strontium

Submitted on January 20, 1964