title: Investigation of Blue Bedding in Cages Housing Treatment-Naïve Hamsters.
abstract: During the acclimation phase of a preclinical safety study involving Syrian golden hamsters, some of the cages of treatment-naïve animals were noted to contain blue-tinged bedding; the urine of these hamsters was not discolored. We sought to understand the underlying cause of this unusual finding to ensure that the study animals were healthy and free from factors that might confound the interpretation of the study. Analysis of extracts from the blue bedding by using HPLC with inline UV detection and high-resolution mass spectrometry indicated that the color was due to the presence of indigo blue. Furthermore, the indigo blue likely was formed through a series of biochemical events initiated by the intestinal metabolism of tryptophan to an indoxyl metabolite. We offer 2 hypotheses regarding the fate of the indoxyl metabolite: indigo blue formation through oxidative coupling in the liver or through urinary bacterial metabolism.
authors.affiliation: Drug Metabolism and Pharmacokinetics, GlaxoSmith-Kline, Research Triangle Park, North Carolina, USA.
authors.forename: Vishal D
authors.initials: VD
authors.lastname: Shah
authors.affiliation: Laboratory Animal Sciences, GlaxoSmith-Kline, Research Triangle Park, North Carolina, USA.
authors.forename: Betsy J
authors.initials: BJ
authors.lastname: Walton
authors.affiliation: Drug Metabolism and Pharmacokinetics, GlaxoSmith-Kline, Research Triangle Park, North Carolina, USA.
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Culp
authors.affiliation: Drug Metabolism and Pharmacokinetics, GlaxoSmith-Kline, Research Triangle Park, North Carolina, USA. steve.x.castellino@gsk.com.
authors.forename: Stephen
authors.initials: S
authors.lastname: Castellino
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000830:Animals, Laboratory; D001512:Bedding and Linens / Q000662:veterinary*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006799:Housing, Animal; D007203:Indigo Carmine / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D014556:Urine / Q000737:chemistry / Q000382:microbiology
chemical_list: D007211:Indoles; C034082:indoxyl; D007203:Indigo Carmine