Cerebral sterols were examined in Wistar strain rats, subjected 4 h, 24h, 14 days or 2 months earlier to severe (2% oxygen) and moderate (7% oxygen) experimental hypoxia. Frombrains of the experimental animals myelin was isolated and examined by gas chromatography coupled withmass spectrometry (GC-MS) to separate and to identify free and esterified (following hydrolysis) cerebralsterols. In both types of hypoxia, the same compounds were identified in fractions of free and esterifiedsterols. Slight differences in sterol content were noted between the two experimental models, involvingcholesterol, the main sterol of the myelin sheath, its smaller sterol precursors (desmosterol, lanosterol)and the less abundant sterols (beta-sitosterol, 24-ethyl-4-cholesten-3-on, cholesta-3,5-dien, cholest-4-en-3-on,22-propyl-3 beta-hydroxy-5,24-cholestadien). Both types (severe and moderate) of hypoxia were found toinduce similar alterations in patterns of cerebral sterols 24 h, 14 days and 2 months following the exposure.Quantitative differences in the sterol pattern were detected only at the very early stage (4 h) of theexperiment.

Keywords: Membrane Lipids - chemistry, Sterols - chemistry, Sterols - metabolism