@entity3957 ( @entity3958 ) is an important brain, lung, and nose toxicant. Inhibition of cytochrome oxidase is the primary biochemical effect associated with lethal @entity3958 exposure. The objective of this study was to evaluate the relationship between the concentration of @entity3287 and cytochrome oxidase activity in target tissues following acute exposure to sublethal concentrations of inhaled @entity3958 . Hindbrain, lung, liver, and nasal (olfactory and respiratory epithelial) cytochrome oxidase activity and @entity3287 concentrations were determined in adult male CD @entity35 immediately after a 3-h exposure to @entity3958 (10, 30, 80, 200, and 400 ppm). We also determined lung @entity3287 and @entity3287 metabolite concentrations at 0, 1.5, 3, 3.25, 3.5, 4, 5, and 7 h after the start of a 3-h @entity3958 exposure to 400 ppm. Lung @entity3287 concentrations increased during @entity3958 exposure and rapidly returned to endogenous levels within 15 min after the cessation of the 400-ppm exposure. Lung @entity3287 metabolite concentrations were transiently increased immediately after the end of the 3-h @entity3958 exposure. Decreased cytochrome oxidase activity was observed in the olfactory epithelium following exposure to > or = 30 ppm @entity3958 . Increased olfactory epithelial @entity3287 concentrations were observed following exposure to 400 ppm @entity3958 . Hindbrain and nasal respiratory epithelial @entity3287 concentrations were unaffected by acute @entity3958 exposure. Nasal respiratory epithelial cytochrome oxidase activity was reduced following acute exposure to > or = 30 ppm @entity3958 . Liver @entity3287 concentrations were increased following exposure to > or = 200 ppm @entity3958 and cytochrome oxidase activity was increased following inhalation exposure to > or = 10 ppm @entity3958 . Our results suggest that cytochrome oxidase inhibition is a sensitive biomarker of @entity3958 exposure in target tissues, and @entity3287 concentrations are unlikely to increase postexposure in the brain, lung, or nose following a single 3-h exposure to < or = 30 ppm @entity3958 .

Cytochrome oxidase inhibition induced by acute @entity3957 inhalation: correlation with tissue XXXX concentrations in the @entity35 brain, liver, lung, and nasal epithelium.

@entity3958 :: ('CHEBI:36945', 'Chemical') :: ['H2S'] @entity3957 :: ('MESH:D006862', 'Chemical') :: ['Hydrogen sulfide'] @entity3287 :: ('CHEBI:26822', 'Chemical') :: ['sulfide'] @entity35 :: ('10116', 'Species') :: ['rats']
@entity3287 :: (CHEBI:26822,Chemical) :: ['sulfide']
