URINE AND URINE-DERIVED COMPOUNDS INDUCE C-FOS MESSENGER-RNA EXPRESSION IN ACCESSORY OLFACTORY-BULB

SOILED bedding from male mice induced c-fos mRNA expression in the acc essory olfactory bulb (AOB) and main olfactory bulb (MOB) of female mi ce. The increase observed in the AOB, but not the MOB, was dependent o n the presence of the vomeronasal organ (VNO). Male urine alone also i ncreased c-fos mRNA expression in the AOB. The urine-derived compounds dehydro-exo-brevicomin (DHB) and sec-butyl-dihydrothiazole (SET) in c ombination with major urinary protein (MUP) induced significantly grea ter c-fos mRNA expression in the AOB than in the MOB. The results indi cate that compounds derived from male urine are detected at the AOB an d suggest that specific urinary compounds play an important role in AO B-mediated reproductive events.