Blood and brain n-pentanol in inhalation exposure.

Male Wistar rats exposed to 100, 300 or 600 p.p.m. n-pentanol vapour for 7 to 14 weeks during five days weekly and 6 hrs daily showed a dose-dependent blood n-pentanol concentration. The brain n-pentanol content was linearly related to the blood pentanol concentrations although this relationship changed after 14 weeks because the brain n-pentanol was significantly smaller than the respective values at 7 weeks. Valeraldehyde, the primary metabolite of n-pentanol, was only found in the brain at the highest vapour dose level. The liver n-pentanol dehydrogenase and 7-ethoxycoumarin O-deethylase activities remained unchanged while kidney ethoxycoumarin deethylase activity was enhanced in a dose-dependent manner at both time points. Brain and muscle acetylcholinesterase activities were increased by the exposure dose-dependently after 7 weeks although this effect ameliorated after 14 weeks. Moderate n-pentanol vapour exposure seems to cause metabolic and functional adaptation in its target organs.