Detoxifying activities in alveolar macrophages of rats treated with acetylcysteine, diethyl maleate and/or aroclor.

Single or sequential treatment of rats with the thiol N-acetyl-L-cysteine (NAC), the glutathione depletor diethyl maleate (DEM) and the enzyme inducer Aroclor 1254 (AR) produced several significant variations on metabolic activities of pulmonary alveolar macrophages (PAM). Specifically, all three compounds elicited an increase in some oxidoreductase activities, including the two dehydrogenases involved in the hexose monophosphate shunt (G6PD and 6PGD) and NADH- or NADPH-dependent diaphorases. Diaphorase activities were especially increased by sequential treatments with AR and DEM or with DEM and NAC. Both NAC and AR also stimulated other detoxifying mechanisms, such as those related to GSH S-transferase activity and to the NADPH-dependent reduction of hexavalent chromium. Therefore, all the monitored parameters were significantly enhanced not only by the enzyme inducer, but also by the thiol, demonstrating its protective role in the biotransformation of mutagenic/carcinogenic compounds.