Abstract
In order to classify the 2-thiobarbituric acid (TBA)-reactive materials in various tissues, control and CCl4-intoxicated rat liver homogenates as well as methyl linoleate hydroperoxide (MLHPO) and malonaldehyde were subjected to the TBA reaction under both aerobic and anaerobic conditions. The TBA reaction of malonaldehyde proceeded regardless of the absence of oxygen, while the TBA value obtained from MLHPO catalyzed by tissue under anaerobic conditions was as low as 15% of the aerobic value, and tissue homogenate, even prepared from CCl4-intoxicated rat liver, gave practically no color development under anaerobic conditions. However, after an aerobic preincubation, MLHPO and tissue homogenate produced TBA-reactive materials which could react with TBA even under anaerobic conditions. These TBA-reactive materials are not malonaldehyde itself but seem to be some further-oxidized and more polar lipid hydroperoxide. The addition of Fe to the TBA reaction medium seems to negate the requirement for oxygen. The magnitude of the TBA value obtained anaerobically from tissue with Fe addition was similar to the TBA value obtained aerobically from tissue without Fe addition.
