THE NUMBER OF INSULTS AND THE CEREBRAL-DAMAGE AFTER HYPOXIA ISCHEMIA ARE ALTERED AFTER ACUTE PRETREATMENT WITH CORTICOSTERONE AND METYRAPONE/

The role of glucocorticoids in neuronal viability is controversial. Mo st studies which describe the effects of glucocorticoids on ischemic b rain damage use surgical adrenalectomy to induce a reduction in plasma corticosterone levels. In the present study we used metyrapone, a cor ticosterone synthesis inhibitor, to examine the effects of acute manip ulation of corticosterone levels on neuronal damage and seizures. Shor tly before transient hypoxia/ischemia, animals were subcutaneously inj ected with sesame oil, metyrapone, corticosterone or corticosterone metyrapone. Both the neuronal damage and the percentage animals with s eizures were found to correlate well with plasma corticosterone levels . This relation between affected area, seizures and corticosterone lev els was confirmed when the rats were re-arranged into animals with and without seizures. However, Corticosterone administration in metyrapon e treated rats did not result (compared to MET treatment) in an increa sed neuronal damage. This suggests that the beneficial effects of mety rapone may be regulated by a corticosterone independent mechanism.