Abstract
Balance studies were used to study changes in calcium and phosphorus metabolism in the chick following the administration of ascorbic acid. The movement of 45Ca and 32P from previously labeled animals was assessed separately as well as the relative retention of Ca and P. Evidence was obtained which indicated that both 45Ca and 32P mobilization and excretion were stimulated in the ascorbate-treated chicks during the initial 24 hours of the study. No such effect was noted at later times. Both compact and cancellous bone tissue, collected at the termination of the experiment, exhibited decreased specific activities of each isotope. It is suggested that the ascorbic acid, either directly or indirectly, effected the mobilization of these isotopes, their excretion and the subsequent bone salt repletion with stable minerals which resulted in the changes of the specific activities. A second response to the injected ascorbic acid, inhibition of phosphorus retention, was of special interest because: contrary to the 32P mobilization effect, it persisted throughout the 4-day study; no effect on calcium retention was noted, thus the effect was more specific; the effect appeared to be the result of an altered phosphorus metabolic pattern after the mineral had reached the blood. The possible implications of such a situation are discussed.