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Calcium Kinetics with Microgram Stable Isotope Doses and Saliva Sampling
Author(s) -
Smith Scott M.,
Wastney Meryl E.,
Nyquist Laurence E.,
Shih ChiYu,
Wiesmann Henry,
Nillen Jeannie L.,
Lane Helen W.
Publication year - 1996
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199611)31:11<1265::aid-jms419>3.0.co;2-j
Subject(s) - chemistry , saliva , isotopes of calcium , calcium , tracer , urine , kinetics , radiochemistry , isotope , blood sampling , chromatography , pharmacokinetics , pharmacology , biochemistry , medicine , organic chemistry , physics , quantum mechanics , nuclear physics
Studies of calcium kinetics require administration of tracer doses of calcium and subsequent repeated sampling of biological fluids. This study was designed to develop techniques that would allow estimation of calcium kinetics by using small (μg) doses of isotopes instead of the more common large (mg) doses to minimize tracer perturbation of the system and reduce cost, and to explore the use of saliva sampling as an alternative to blood sampling. Subjects received an oral dose (133 μg) of 43 Ca and an i.v. dose (7.7 μg) of 46 Ca. Isotopic enrichment in blood, urine, saliva and feces was well above thermal ionization mass spectrometry measurement precision up to 170 h after dosing. Fractional calcium absorptions determined from isotopic ratios in blood, urine and saliva were similar. Compartmental modeling revealed that kinetic parameters determined from serum or saliva data were similar, decreasing the necessity for blood samples. It is concluded from these results that calcium kinetics can be assessed with μg doses of stable isotopes, thereby reducing tracer costs and with saliva samples, thereby reducing the amount of blood needed.