title: Analysis of creatine, creatinine, creatine-d3 and creatinine-d3 in urine, plasma, and red blood cells by HPLC and GC-MS to follow the fate of ingested creatine-d3.
abstract: Creatine, which is increasingly being used as an oral supplement, is naturally present in the body. Studies on the fate of a particular dose of creatine require that the creatine be labeled, and for studies in humans the use of a stable isotopic label is desirable. The concentrations of total creatine and total creatinine were determined using HPLC. Creatine and creatinine were then separated using cation exchange chromatography and each fraction was derivatized with trifluoroacetic anhydride and the ratio of the deuterated:undeuterated species determined using GC-MS. Ratios of creatine:creatine-d(3), and creatinine:creatinine-d(3), and the concentrations of each of these species, were able to be determined in urine, plasma and red blood cells. Thus, the uptake of labeled creatine into plasma and red blood cells and its excretion in urine could be followed for a subject who ingested creatine-d(3). Creatine-d(3) was found in the plasma and red blood cells 10 min after ingestion, while creatine-d(3) and creatinine-d(3) were found in the urine collected after the first hour.
authors.affiliation: Department of Human Kinetics, St. Francis Xavier University, Antigonish, Nova Scotia, Canada B2G 2W5.
authors.forename: Lauren
authors.initials: L
authors.lastname: MacNeil
authors.forename: Lisa
authors.initials: L
authors.lastname: Hill
authors.forename: Daniel
authors.initials: D
authors.lastname: MacDonald
authors.forename: Lori
authors.initials: L
authors.lastname: Keefe
authors.forename: James F
authors.initials: JF
authors.lastname: Cormier
authors.forename: Darren G
authors.initials: DG
authors.lastname: Burke
authors.forename: Truis
authors.initials: T
authors.lastname: Smith-Palmer
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002852:Chromatography, Ion Exchange; D003401:Creatine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003404:Creatinine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003903:Deuterium; D004912:Erythrocytes / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male
chemical_list: D003903:Deuterium; D003404:Creatinine; D003401:Creatine