Hepatic content, activity, and gene expression of xanthine oxidase (XO). Hepatic content of XO (a) was expressed as its concentration in the supernatant of liver extract. Hepatic XO activity (b) was calculated according to the XO protein ratio and expressed as U/g protein. Relative gene expression (c) was determined by RT-PCR and shown in the graph as the amounts of initial template. Data are expressed as mean ± SD. when the DM group was compared with CON or CON + Fx group, when DM + Fx group was compared with CON or CON + Fx, and when compared with DM group, respectively.