Iron- and lactic acid-induced lipid peroxidation in rat kidney homogenates and slices

Lactic acid 4 mM acted as a lipoperoxidant by increasing production of thiobarbituric acid-reactive substances (TBARS) in rat kidney slices and homogenates. This effect occurred mainly when slices and homogenates were incubated in a pH 5.4 medium conductive to full expression of compound acidity. TBARS increase was only slight when incubation was performed in Krebs buffer, pH 7.4. Moreover, sodium lactate 4 mM increased TBARS production only when homogenates were incubated in the pH 5.4 medium. Deferoxamine (1 mM) inhibited the prooxidant effect of lactic acid 4 mM, and TBARS increase was correlated with iron release. The iron mobilized may come from reserves where it is weakly bound or from ferritin; and ascorbic acid, present in low quantities in kidney, might trigger the release of this product.