STABLE ISOTOPIC MEASUREMENT OF ENDOGENOUS FECAL CALCIUM EXCRETION IN CHILDREN

Using a stable isotopic technique in which Ca-42 was administered via a bolus injection, we measured endogenous fecal calcium excretion, V(f), in five healthy children, aged 3-14 years. The V(f) averaged 1.4 +/- 0.4 mg/kg/day, and was lower than urinary Ca excretion (V(u)) in four of the five children. These results for V(f) are consistent with previously reported results for V(f) in healthy adults and much lower than those reported in premature infants. These results may be useful in understanding developmental changes in Ca metabolism and in interpreting dual tracer Ca isotope studies in children.