Comparison of the plasma concentration and urinary excretion of strontium and calcium in man.

Abstract

SummaryThe relatively short-lived, radioactive isotope of strontium, strontium-87m (T½ = 2·7 hours) was used to measure plasma concentration and urinary excretion in man, up to six hours after a dose of 5 µc. The radiation dose to the tissues was quite small, so that successive experiments were made on a given subject.The isotope was taken by mouth in several ways: after a fasting period, between meals, with a meal, and in some experiments after a daily ingestion of 10 mg of stable strontium.The plasma concentration and urinary excretion of calcium were also measured, so that the renal discrimination between strontium and calcium could be derived.The renal clearance of strontium varied only some 20 per cent for a given subject, despite the changes in the experimental conditions, but varied from 5·3 to 10·8 litres/day from individual to individual. The renal discrimination between strontium and calcium was more constant, however, ranging from 2·8 to 4·3, the mean value being 3·5.