Effects of single and repeated cigarette smoke-exposures on the activities of aryl hydrocarbon hydroxylase, epoxide hydratase and UDP glucuronosyltransferase in rat lung, kidney and small intestinal mucosa.

A single exposure to cigarette smoke for one hour decreased the pulmonary microsomal epoxide hydratase activity in rats. A more rapid decrease was seen after 5 consecutive exposures, one hour daily. Meanwhile, the activity of pulmonary aryl hydrocarbon hydroxylase (AHH) increased several fold. In small intestinal mucosa the activities of AHH and epoxide hydratase were enhanced both by single and repeated cigarette smoke-exposures. In kidney the activity of AHH increased, whereas neither that of epoxide hydratase nor of UDP glucuronosyltransferase changed. In small intestinal mucosa the activity of UDP glucuronosyltransferase increased after repeated smoke-exposures, but in lung no clear change in the UDP glucuronosyltransferase activity was detected.