KERATINOCYTE SUPEROXIDE GENERATION

We have demonstrated using the reduction of cytochrome c, that the ker atinocyte cell line H357 generates superoxide at significant rates (8. 36 nmol/h/10(6) cells). The rate of superoxide release decreased as th e cells reached confluence. Superoxide production was increased more t han twofold following preincubation with IL-1 beta, or by the addition of the Ca2+ ionophore, Ionomycin. Other stimuli known to activate the NADPH oxidase of phagocytes were ineffective, but the regulatory cyto kine IFN gamma lowered the rate of release. Inhibitors of lipoxygenase function decreased the rate of superoxide production, whereas inhibit ors of cyclo-oxygenase, xanthine oxidase, or NADPH oxidase failed to i nhibit. The addition of NADH or NADPH to whole cells increased the rat e threefold. (C) 1998 Elsevier Science Inc.