The influence of phenobarbital on cytochromes and reactive oxygen species in erythropoietin producing HepG2

Light absorption photometry of HepG2 cells treated with phenobarbital for e nhancing the content of cytochrome P-450 and the synthesis of erythropoieti n revealed an influence on all cytochromes detectable in the wavelength ran ge between 400 and 620 nm, No correlation was found between specific change s of cytochrome P-450 absorption and increased EPO synthesis as proposed ea rlier by Fandrey et al, (Life Sci, (1990) 47, 127-134), In the present stud y, however, the increased erythropoietin synthesis could be related to a de creased intracellular hydroxyl radical level described as crucial for the o xygen regulated gene expression (Kietzmann et al,, Biochem, J, (1998) 335, 425-432; Porwol et al., Eur. J, Biochem, (1998) 256, 16-23), (C) 1998 Feder ation of European Biochemical Societies.