title: Quantification of L-abrine in human and rat urine: a biomarker for the toxin abrin.
abstract: Abrin is a toxic protein found in the jequirity seed. L-Abrine (N-methyl-tryptophan) is also found in the jequirity seed and can be used as a biomarker for abrin exposure. Analysis of L-abrine was added to an existing method for quantifying ricinine as a marker for ricin exposure in human urine and analytically validated. Accuracy and reproducibility were enhanced by including a newly synthesized (13)C(1)(2)H(3)-L-abrine internal standard. One-milliliter urine samples were processed using solid-phase extraction prior to a 6-min high-performance liquid chromatography separation. Protonated molecular ions were formed via electrospray ionization in a triple-quadrupole mass spectrometer and quantified via multiple reaction monitoring. Method validation included the characterization of two enriched urine pools, which were used as quality control materials. Endogenous levels of L-abrine were quantified in a reference range of 113 random urine samples at 0.72 +/- 0.51 ng/mL. Urinary concentrations of L-abrine were monitored in an intentional rat exposure study for up to 48 h. Comparing the results from the human reference range and the animal exposure study indicates that this method is suitable for quantifying L-abrine within 24 h post-exposure. Quantification of L-abrine beyond 24 h is limited by rapid excretion of the biomarker and the level of the L-abrine dose.
authors.affiliation: Division of Laboratory Sciences, Centers for Disease Control and Prevention, 4770 Buford Highway, MS F44, Atlanta, Georgia 30341, USA. rmj6@cdc.gov
authors.forename: Rudolph C
authors.initials: RC
authors.lastname: Johnson
authors.forename: Yingtao
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ram
authors.initials: R
authors.lastname: Jain
authors.forename: Sharon W
authors.initials: SW
authors.lastname: Lemire
authors.forename: Shannon
authors.initials: S
authors.lastname: Fox
authors.forename: Pat
authors.initials: P
authors.lastname: Sabourin
authors.forename: John R
authors.initials: JR
authors.lastname: Barr
mesh_terms: D000036:Abrin / Q000652:urine*; D029912:Abrus / Q000737:chemistry / Q000506:poisoning; D000818:Animals; D015415:Biomarkers / Q000652:urine; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D026121:Indole Alkaloids / Q000652:urine*; D008297:Male; D015394:Molecular Structure; D011041:Poisoning / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D012015:Reference Standards; D015203:Reproducibility of Results; D012639:Seeds / Q000737:chemistry / Q000506:poisoning; D052616:Solid Phase Extraction; D013237:Stereoisomerism
chemical_list: D015415:Biomarkers; D026121:Indole Alkaloids; D000036:Abrin; C496492:abrine