Effect of Orally and Intravenously Administered Stable Strontium on⁹⁰ Sr Metabolism in Man

The effect of orally and of intravenously administered stable strontium on⁹⁰ Sr metabolism was investigated in man under strictly controlled dietary conditions. The oral dose of stable strontium averaging 1517 mg/day was given as the lactate for 24-48 days. Intravenous infusions of stable strontium as the gluconate were given in 500 ml 5% glucose in water over 4 hours on 6 consecutive days. The amounts of stable strontium infused per day were 318, 612, 954, and 1200 mg, respectively.⁹⁰ Sr and calcium balances were determined before and during the oral and intravenous administration of stable strontium. Stable strontium given orally or intravenously increased the urinary⁹⁰ Sr excretion. This increase was greater when stable strontium was given intravenously than orally, the average factor of increase being 3 and 1.65 in the two studies, respectively. The fecal⁹⁰ Sr excretions did not increase during either oral or intravenous administration of stable strontium. The⁹⁰ Sr balances changed little during the oral intake of stable strontium while they became more negative during the infusions of stable strontium. The urinary calcium increased during the oral or intravenous administration of stable strontium and this increase was greater when stable strontium was given intravenously than orally.