Oxygen radicals, and related species that stimulate cell proliferation

Oxygen radicals, and related species that stimulate cell proliferation 

Active oxygen species Cell type Stimulus3 Ref. 

12-0-tetradecanoylphorbol-13-acetate PDGF, platelet-derived growth factor 

Despite the well-studied respiratory burst it is now clear that superoxide is also released by a variety of non-phagocytic cells. For example human B-lympho-cytes, which have been transformed by Epstein-Barr virus, express a super-oxide-generating system similar in many respects to the NADPH-oxidase of neutrophils [80]. This oxidase in lymphocytes can be stimulated by cytokines, suggesting that superoxide release may be a normal function of these B-lympho-cytes [81], NADPH-oxidase also occurs in normal peripheral B-lymphocytes, but disappears from the cell surface during final differentiation to plasma cells. 

Superoxide is also released from cells other than leukocytes (Table 3). For instance primary human fibroblasts release superoxide at a rate similar to 

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