Fig. 2.

Age-dependence of thiol/disulfide ratios in plasma. Panel A: Age vs GSH/GSSG, r = −0.5, two-tailed p values < 0.001; panel B: Age vs cysteine/cystine, r = −0.315, two-tailed p values < 0.01 panel C: Age vs cysteinylglycine/cystinylglycine, r = −0.708, two-tailed p values < 0.0001; panel D: Age vs PTI, r = 0.686, two-tailed p values < 0.0001. Data from Refs. [22] (red symbols), [58] (green), [61] (blue), [62] (pink). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)