Effects of ageing on metabolite and oxidant concentrations in different regions of rat kidney under normal and stress conditions.

Metabolic and oxidative stresses have been implicated in ageing and the pathogenesis of chronic kidney disease. In this study, we investigated the glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and lactate concentrations in different kidney regions under control conditions and after exposure to oxidative stress invoked by 0.2 mM H2O2. Slices of superficial cortex, outer or inner medulla were dissected from kidneys of male Wistar rats of 5-, 12-, 36- and 60-week old. Samples were incubated for 30 min ± 0.2 mM H2O2 prior to homogenisation and centrifugation. The concentrations of GSH, TBARS and lactate were measured by colorimetry. Each metabolite showed a distinctive pattern. For GSH, this was 12 weeks > 36 weeks > 60 weeks and 5 weeks with the highest concentration measured in the superficial cortex at 12 weeks. For TBARS and lactate, the pattern was for the lowest concentration at 12 weeks and the highest at 60 and 5 weeks. The highest lactate and TBARS concentrations were measured under oxidative stress conditions, particularly at 5 and 60 weeks. These results suggest that GSH in different kidney regions peaks at maturity and then reduces with increasing age.