THE LIPID-PEROXIDATION IN VARIOUS PARTS OF THE RAT-BRAIN - EFFECT OF AGE, HYPOXIA AND HYPEROXIA

The effect of normobaric oxygen atmosphere on hypoxia-enhanced lipid p eroxidation in the brain cortex, subcortical structures, medulla oblon gata and in the cerebellum was observed in 7- and 21-day-old and adult rats. The production of free oxygen radicals causing lipid peroxidati on was assessed by the method described by Ohkawa et al. (1979). The r ats were exposed for 30 min to 100 % oxygen atmosphere which significa ntly stimulated the production of malondialdehyde (MDA) in all the stu died regions of the brain in 7- and 21-day-old male rats, and in the b rain cortex and subcortical structures of adult males. Higher levels o f MDA were found in the brain cortex of 7-day-old female rats only. Re oxygenation with pure oxygen after 30 min hypobaric hypoxia correspond ing to 9000 m increased MDA production in all studied parts of the bra in on both male and female rats 7- and 21 -day-old. In adult rats sign ificantly increased MDA production was only found in the brain cortex of male and female rats and in the subcortical structures of males. Th e exposition to hypobaric hypoxia followed by reoxygenation by atmosph eric air enhanced MDA production in all studied regions of the brain i n 7-day-old males and in the cerebellum of females; in 21-day-old rats of both sexes a significant increase of MDA was detected in all parts of the brain. In adult rats were found higher MDA levels in the cereb ral cortex of both males and females.