GSH and GSSG levels in plantaris muscles. Chronic alcohol ingestion for 6 weeks decreased the available pool of GSH (A), but had no effect on GSSG levels (B). The GSSG/GSH ratio, a marker of the oxidative state of the GSH pool, was unchanged between the groups (C). Values are expressed as mean + SEM. GSH, glutathione; GSSG, glutathione disulfide; EtOH, alcohol-fed rats; PRO, procysteine-supplemented rats. Significant difference (P < 0.05) is shown compared with control group (*).