title: An improved HPLC method for the investigation of L-selenomethionine metabolism in rat gut contents.
abstract: Selenomethionine (SeMet) is a widely used nutritional supplement that has potential benefit for people living in selenium-deficient areas. Previous research has shown that selenium administered as SeMet undergoes significant enterohepatic recycling which may involve the gut microflora. In order to investigate this we have developed a simple method for the quantitation of l-SeMet in rat gut content suspensions prepared from jejunum, ileum, caecum and colon. After incubation of l-SeMet with gut content suspensions, samples were deproteinized with sulfosalicylic acid and derivatized with o-phthaldialdehyde (OPA) and N-acetyl-l-cysteine (NAC). Mass spectrometry confirmed the formation of a 1:1:1 derivative of l-SeMet with OPA and NAC. Samples were analysed by reversed-phase high-performance liquid chromatography with fluorescence detection. The assay was linear in the concentration range 0.5-100 microg/mL (r(2) = 0.9992) with a limit of detection of 0.025 microg/mL (signal-to-noise ratio of 5). Intra-day and inter-day accuracies were 91.1-92.8 and 91.7-95.5%, respectively with corresponding precisions as relative standard deviation of <5%. Incubation of l-SeMet with gut content suspensions from different parts of the rat intestine showed that l-SeMet metabolism occurs mainly in the caecum.
authors.affiliation: School of Pharmacy, University of Otago, Dunedin, New Zealand. pummy.krittaphol@otago.ac.nz
authors.forename: Woravimol
authors.initials: W
authors.lastname: Krittaphol
authors.forename: Arlene
authors.initials: A
authors.lastname: McDowell
authors.forename: Christine D
authors.initials: CD
authors.lastname: Thomson
authors.forename: Ian G
authors.initials: IG
authors.lastname: Tucker
authors.forename: J Paul
authors.initials: JP
authors.lastname: Fawcett
authors.forename: Momir
authors.initials: M
authors.lastname: Mikov
mesh_terms: D000111:Acetylcysteine / Q000737:chemistry; D000818:Animals; D001557:Benzenesulfonates; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005766:Gastrointestinal Contents / Q000737:chemistry*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012459:Salicylates / Q000737:chemistry; D012645:Selenomethionine / Q000032:analysis / Q000378:metabolism*; D012680:Sensitivity and Specificity; D009764:o-Phthalaldehyde / Q000737:chemistry
chemical_list: D001557:Benzenesulfonates; D012459:Salicylates; D009764:o-Phthalaldehyde; D012645:Selenomethionine; C003366:sulfosalicylic acid; D000111:Acetylcysteine