Secretion of Sr 85 and Ca 47 in Human Saliva. ∗

Abstract

Summary

In a study of secretion of Sr⁸⁵ and of Ca⁴⁷ in saliva, the ratio of saliva concentration to plasma concentration varied from 1/5 to 1/3 for Sr⁸⁵ and from 2/5 to almost unity for Ca⁴⁷. The average ratios favored secretion of Ca⁴⁷ by a factor of more than 2, the difference in secretion of the 2 isotopes being highly significant. Values for Ca⁴⁷ were in accord with the levels of stable calcium found by us in saliva and previously reported by others. No difference in Sr⁸⁵/Ca⁴⁷ ratios of saliva in relation to plasma was found between patients on low and on high Ca intake. The high degree of discrimination of the salivary glands against the secretion of Sr⁸⁵ contrasts with the action of the kidneys in favoring secretion of Sr⁸⁵ over that of radiocalcium by a factor of approximately 3 to 1.