title: Detection of metabolic fluxes of O and H atoms into intracellular water in mammalian cells.
abstract: Metabolic processes result in the release and exchange of H and O atoms from organic material as well as some inorganic salts and gases. These fluxes of H and O atoms into intracellular water result in an isotopic gradient that can be measured experimentally. Using isotope ratio mass spectroscopy, we revealed that slightly over 50% of the H and O atoms in the intracellular water of exponentially-growing cultured Rat-1 fibroblasts were isotopically distinct from growth medium water. We then employed infrared spectromicroscopy to detect in real time the flux of H atoms in these same cells. Importantly, both of these techniques indicate that the H and O fluxes are dependent on metabolic processes; cells that are in lag phase or are quiescent exhibit a much smaller flux. In addition, water extracted from the muscle tissue of rats contained a population of H and O atoms that were isotopically distinct from body water, consistent with the results obtained using the cultured Rat-1 fibroblasts. Together these data demonstrate that metabolic processes produce fluxes of H and O atoms into intracellular water, and that these fluxes can be detected and measured in both cultured mammalian cells and in mammalian tissue.
authors: Pacific Northwest National Laboratory, Richland, Washington, United States of America. helen.kreuzer@pnnl.gov
authors: Helen W
authors: HW
authors: Kreuzer
authors: Luca
authors: L
authors: Quaroni
authors: David W
authors: DW
authors: Podlesak
authors: Theodora
authors: T
authors: Zlateva
authors: Nikki
authors: N
authors: Bollinger
authors: Aaron
authors: A
authors: McAllister
authors: Michael J
authors: MJ
authors: Lott
authors: Eric L
authors: EL
authors: Hegg
mesh_terms: D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014867:Water / Q000737:chemistry* / Q000378:metabolism
chemical_list: D014867:Water; D006859:Hydrogen; D010100:Oxygen