Induction by cigarette smoke of aryl hydrocarbon hydroxylase activity in the rat kidney and lung

In both the rat kidney and lung, inhalation of cigarette smoke diluted with air (1/15) for a limited period of time (15 min) specifically induces aryl hydrocarbon hydroxylase (AHH)2 in less than 4 h. Up to four successive inhalations administered at 2-h intervals activities. The maximal effect corresponds to about 10 times the control value. Compared to the kidney enzyme, the lung AHH activity is about three or four time more sensitive to small concentrations of cigarette smoke. The biological half-life of the lung AHH activity is longer than 24 h, while it is only 3-4 h in the kidney. In both tissues, the induced enzyme presents the same in vitro thermolability and sensitivity to various inhibitors. For the establishment of the AHH induction, protein synthesis is continuously required, while RNA synthesis is only necessary during the first 2 h following the smoke treatment.