FREE STEROLS IN THE RAT WHITE-MATTER FOLLOWING EXPERIMENTAL GLOBAL-ISCHEMIA

The pattern of free sterols occurring in the cerebral white matter was studied in an experimental model of global ischemia that was induced in rats by means of the method described by KORPACHEV et al. (1982). S terol isolation, separation and identification was accomplished by sui table extraction procedures followed by gas-chromatography-mass spectr ometry of the purified sterol extracts. It has been shown that the per centage of lanosterol happened to decrease sharply following the ische mic state and other sterols, typically occurring in maturating brains and absent in the control brain specimens from adult rats, such as 4,4 -dimethylcholesterol, 4,4-dimethylcholest-5,8,24-triene-3 beta-ol and 4,4,14-trimethylcholest-5,8-diene-3 beta-ol happened to appear. The ap pearance of these forms of free sterols in the postischemic brain is i nterpreted as a biochemical exponent of regeneration processes occurri ng in the white matter membranes following the injury suffered during the experimental heart arrest.