Cigarette smoke decreases inducible nitric oxide synthase in lung epithelial cells.

Cigarette smoking has been associated with decreased exhaled nitric oxide (NO). To investigate the mechanism of this decrease, the effects of a cigarette smoke extract were evaluated a murine lung epithelial cell line (LA-4), a human lung epithelial cell line (A549), and primary cultures of human lung epithelial cells induced to produce NO by cytokines. NO production was evaluated by measuring nitrite, a stable end product of NO, in cell culture supernatant fluids.