title: Recent studies of human calcium metabolism using stable isotopic tracers.
abstract: Stable isotopes of calcium are used safely as tracers for calcium in human populations ranging in age from infants to postmenopausal women. Thermal ionization mass spectrometry is used to measure calcium isotope ratios with relative accuracies of about 1% for natural abundance ratios at precisions of about 1% relative to the mean. Perturbations of natural abundance ratios are determined for the calcium in blood, urine, and feces with a limit of detection of about 2 delta % excess. The mathematical rationale for clinical studies of fractional absorption of dietary calcium and the kinetics of calcium's internal distribution are presented.
authors.affiliation: National Institutes of Health, Bethesda, MD 20892.
authors.forename: A L
authors.initials: AL
authors.lastname: Yergey
authors.forename: S A
authors.initials: SA
authors.lastname: Abrams
authors.forename: N E
authors.initials: NE
authors.lastname: Vieira
authors.forename: R
authors.initials: R
authors.lastname: Eastell
authors.forename: L S
authors.initials: LS
authors.lastname: Hillman
authors.forename: D G
authors.initials: DG
authors.lastname: Covell
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D002127:Calcium Isotopes; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D013058:Mass Spectrometry; D008892:Milk / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D002127:Calcium Isotopes; D002118:Calcium