title: Technical note: quantification of plasma 1- and 3-methylhistidine in dairy cows by high-performance liquid chromatography-tandem mass spectrometry.
abstract: To improve monitoring of protein mobilization in dairy cows, we developed and evaluated a method to quantify 1-methylhistidine and 3-methylhistidine in plasma by HPLC-tandem mass spectrometry. The analytical method described is (1) sensitive: both histidine derivates can be detected in the picomole range; (2) accurate: intra- and interassay coefficients of variation were < 5% for all standard solutions of 1-methylhistidine and 3-methylhistidine measured (31 to 500 pmol); (3) specific: 1-methylhistidine is clearly separated from 3-methyl-histidine in plasma samples from dairy cows; and (4) flexible: can be easily adapted to measure other amino acids or compounds containing a primary amine. 1-Methylhistidine is present in plasma of dairy cows at concentrations of 5.0 ± 1.7 μM, similar to concentrations of 3-methylhistidine (4.4 ± 2.4 μM). Analytical separation of both histidine metabolites is essential when plasma 3-methylhistidine is used as indicator for muscle breakdown in dairy cows. Specific quantification of the concentration of 3-methylhistidine in bovine plasma samples by HPLC tandem mass spectrometry can improve monitoring of protein mobilization in dairy cows.
authors.affiliation: Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, PO Box 80176, 3508 TD Utrecht, the Netherlands. M.Houweling@uu.nl
authors.forename: M
authors.initials: M
authors.lastname: Houweling
authors.forename: S G A
authors.initials: SG
authors.lastname: van der Drift
authors.forename: R
authors.initials: R
authors.lastname: Jorritsma
authors.forename: A G M
authors.initials: AG
authors.lastname: Tielens
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D005260:Female; D008762:Methylhistidines / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000662:veterinary
chemical_list: D008762:Methylhistidines; C028120:1-methylhistidine; C028118:3-methylhistidine