DEVELOPMENTAL-CHANGES IN THE PEROXIDATION POTENTIAL OF RAT-BRAIN HOMOGENATE AND MITOCHONDRIA

Lipid peroxidation, one of the most common expressions of oxidative st ress, may be altered during normal physiological states including deve lopment. We have examined the changes in lipid peroxidation in rat bra in, a tissue highly susceptible to oxidative damage, during this physi ological state. In vivo lipid peroxidation was moderate in the foetal and neonatal period and increased during the postnatal development. Li pid peroxidation potential in brain homogenate and mitochondria, in Tr is-HCl buffer or with exogenous cofactors, such as ascorbate-Fe2+, NAD PH ADP-Fe3+ and cumene hydroperoxide, showed significant changes durin g pre- and postnatal development. In general, brain as well as liver ( used as a standard tissue for comparision) seem to have low peroxidati on potential in the foetal and neonatal period which then increases at different rates during development to reach adult values at different days. The low peroxidation potential corresponds to the rapid phase o f cell proliferation. These results taken together with similar earlie r finding in other systems may indicate a possible occurrence of a 'pe rmissible period' during which the low levels of lipid peroxidation ma y be able to yield only low amounts of cytostatic aldehydes and peroxi des as byproducts, thereby allowing rapid proliferation of cells.