title: Determining biological tissue turnover using stable isotopes: the reaction progress variable.
abstract: The reaction progress variable is applied to stable isotope turnover of biological tissues. This approach has the advantage of readily determining whether more than one isotope turnover pool is present; in addition, the normalization process inherent to the model means that multiple experiments can be considered together although the initial and final isotope compositions are different. Consideration of multiple isotope turnover pools allows calculation of diet histories of animals using a time sequence of isotope measurements along with isotope turnover pools. The delayed release of blood cells from bone marrow during a diet turnover experiment can be quantified using this approach. Turnover pools can also be corrected for increasing mass during an experiment, such as when the animals are actively growing. Previous growth models have been for exponential growth; the approach here can be used for several different growth models.
authors.affiliation: Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0111, USA. tcerling@earth.utah.edu
authors.forename: Thure E
authors.initials: TE
authors.lastname: Cerling
authors.forename: Linda K
authors.initials: LK
authors.lastname: Ayliffe
authors.forename: M Denise
authors.initials: MD
authors.lastname: Dearing
authors.forename: James R
authors.initials: JR
authors.lastname: Ehleringer
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Passey
authors.forename: David W
authors.initials: DW
authors.lastname: Podlesak
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Torregrossa
authors.forename: Adam G
authors.initials: AG
authors.lastname: West
mesh_terms: D000818:Animals; D004032:Diet; D006128:Growth / Q000502:physiology*; D007554:Isotopes / Q000378:metabolism / Q000493:pharmacokinetics*; D008954:Models, Biological; D013997:Time Factors
chemical_list: D007554:Isotopes