The antioxidant effects of copper sulphate on the actions of a phorbol ester and a xanthine-xanthine oxidase superoxide-anion generating system in murine epidermal cells.
Aqueous solutions of CuSO(4) were shown to inhibit cytochrome c reduction by xanthine-xanthine oxidase. Such copper solutions also significantly inhibited oxidant production, induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), measured as chemiluminescence, in murine epidermal cells in vitro. At the non-toxic level of 250 mum, CuSO(4) inhibited by 40% the induction of ornithine decarboxylase by TPA in murine epidermal cultures. The superoxide generating system xanthine-xanthine oxidase was shown to induce ornithine decarboxylase by two- to threefold; such induction was partially inhibited by CuSO(4). Superoxide dismutase slightly inhibited TPA-induced, but not basal DNA synthesis in cultured epidermal cells. For unknown reasons, DNA synthesis was enhanced by CuSO(4) alone and was further enhanced in the presence of TPA. It appears that oxidants generated in response to TPA partially mediate the induction of ornithine decarboxylase and to a lesser extent DNA synthesis.
Fischer
S M
SM
University of Texas System Cancer Center, Science Park-Research Division, Smithville, TX 78957, USA.
Kokolus
W J
WJ
Baldwin
J K
JK
Patrick
K E
KE