DEVELOPMENTAL-CHANGES IN ENZYMATIC SYSTEMS INVOLVED IN PROTECTION AGAINST PEROXIDATION IN ISOLATED RAT-BRAIN MICROVESSELS

Activities of 3 enzymes involved in the major detoxification pathway for peroxides were assessed in rat brain microvessels. Between the 7th and 60th day after birth, glutathione peroxidase specific activity remained constant in microvessels, while glutathione reductase specific activity increased from day 14 to day 60. On the other hand, the specific activity of these two enzymes evolved similarly in total brain homogenate: they increased between day 7 and day 30, and then reached a plateau. In contrast, catalase specific activity in microvessels was markedly decreased from day 7 to day 60. A significant decrease in this enzyme specific activity was also observed in brain homogenate during development. However, in microvessels, catalase specific activity remained higher than that of brain homogenate throughout the time period studied. Our results support the idea that enzymatic mechanisms against peroxidative damage are required in early age, and could be potent at the level of the blood-brain barrier.