Association between serum γ-glutamyltransferase and oxidative stress related factors

Background/Aims: To investigate the main factors correlated with the serum γ-glutamyltransferase activity. Methodology: We measured serum γ-glutamyltransferase activity in 248 healthy Japanese people and determined its correlations with serum antioxidants, other plasma or serum factors, urinary 8-hydroxydeoxyguanine, and lifestyle factors. Results: The mean serum γ-glutamyltransferase activity was 29 IU/L. γ- Glutamyltransferase activities of males and persons older than 45 years were significantly higher than each counterpart. γ-Glutamyltransferase levels increased significantly with the number of cigarettes smoked per day and the frequency of alcohol consumption except for the persons who did not take alcohol. Additionally, γ-glutamyltransferase significantly correlated with urinary 8-hydroxydeoxyguanine, and with more blood factors including serum tocopherols, carotenoids, antioxidative enzymes, lipid peroxide, and free fatty acids than urinary 8-hydroxydeoxyguanine did. In multiple regression analyses, γ-glutamyltransferase had significant associations with retinol, 8-hydroxydeoxyguanine, docosahexaenoic acid, and cigarette smoking. Conclusions: Our present findings support the hypothesis that γ-glutamyltransferase can be used as a marker related with oxidative stress.