title: Butylated hydroxytoluene is a ligand of urinary proteins derived from female mice.
abstract: Mice secrete substantial amounts of protein, particularly proteins called the major urinary proteins (MUPs), in urine. One function of MUPs is to sequester volatile pheromone ligands, thereby delaying their release and providing a stable long-lasting signal. Previously, only MUPs isolated from male mice have been used to identify ligands. Here, we tested the hypothesis that MUPs derived from females may also sequester volatile organic compounds. We identified butylated hydroxytoluene (BHT), a synthetic antioxidant present in the laboratory rodent diet, as a major ligand bound to urinary proteins derived from C57BL/6J female urine. BHT was also bound to the male-derived proteins, but the binding was less prominent than that in female urine, even though males express approximately 4 times more proteins than females. We confirmed that the majority of BHT in female urine was associated with the high molecular weight fraction (>10 kDa) and the majority of the proteins that sequestered BHT were MUPs as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The sequestration of BHT by MUPs was further confirmed by employing the recombinant MUP8 whose natural analogue has been reported in both sexes. Therefore, our data indicate that MUPs expressed in both sexes can bind, transport, and excrete xenobiotics into urine and raise the possibility that in addition to the known role in chemical communication, MUPs function as a defense mechanism against exogenous toxins.
authors.affiliation: Monell Chemical Senses Center, Philadelphia, PA 19104, USA. jkwak@monell.org
authors.forename: Jae
authors.initials: J
authors.lastname: Kwak
authors.forename: Jesusa
authors.initials: J
authors.lastname: Josue
authors.forename: Adam
authors.initials: A
authors.lastname: Faranda
authors.forename: Maryanne Curran
authors.initials: MC
authors.lastname: Opiekun
authors.forename: George
authors.initials: G
authors.lastname: Preti
authors.forename: Kazumi
authors.initials: K
authors.lastname: Osada
authors.forename: Kunio
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Gary K
authors.initials: GK
authors.lastname: Beauchamp
mesh_terms: D000818:Animals; D002084:Butylated Hydroxytoluene / Q000737:chemistry* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D008024:Ligands; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011506:Proteins / Q000378:metabolism*; D055549:Volatile Organic Compounds / Q000737:chemistry
chemical_list: D008024:Ligands; D011506:Proteins; D055549:Volatile Organic Compounds; C035737:major urinary proteins; D002084:Butylated Hydroxytoluene