title: Improved methodology to assay carnitine and levels of free and total carnitine in human plasma.
abstract: Carnitine, once known as vitamin Bt, is intrinsic to human tissue and is biochemically established as being acylated with fatty acids by Acyl-CoA to give Acyl-carnitines which then are transported to the inner mitochondrial membrane by a translocase. Carnitine is of increasing clinical interest and importance, and endomyocardial deficiencies of carnitine have been reported for patients in heart failure. Consequently, a reproducible and accurate analysis of human tissue specimens for levels of free carnitine and Acyl-carnitine to guide and to support continuing clinical studies of disease states is needed. We have devised an analytical method which utilizes 5,5'-dithiobis-2-nitro-benzoate and demonstrated recovery, reproducibility and precision. Hydrolysis of a specimen at 90 degrees C for 15 min, and control of pH below 6.0 are critical steps. The mean levels of free carnitine and total carnitine in 17 ordinary subjects were 50.6 +/- 9.7 nmol./ml and 62.6 +/- 11.7 nmol./ml. respectively.
authors.affiliation: Institute for Biomedical Research, University of Texas, Austin 78712.
authors.forename: L J
authors.initials: LJ
authors.lastname: Xia
authors.forename: K
authors.initials: K
authors.lastname: Folkers
mesh_terms: D000108:Acetylcarnitine / Q000097:blood*; D002331:Carnitine / Q000097:blood* / Q000302:isolation & purification; D004355:Drug Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007202:Indicators and Reagents; D012016:Reference Values; D013053:Spectrophotometry / Q000379:methods
chemical_list: D007202:Indicators and Reagents; D000108:Acetylcarnitine; D002331:Carnitine