24‐Hydroxycholesterol levels in human brain1

24‐H ydroxycholesterol (cerebrosterol, cholest‐5‐ene‐3β;, 24ξ‐diol) occurs at low levels in human (D i F risco , D e R uggieri and E rcoli , 1953; E rcoli and D e R uggieri , 1953a, 19536; S chubert , R ose and B urger , 1961; V an L ier and S mith , 1969 , 1970), equine (E rcoli , D i F risco and D e R uggieri , 1953a; E rcoli and D e R uggieri , 1953a, 1953b; F ieser , H uang and B hattacharyya , 1957) and bovine (R ichter and D annenberg , 1969) brain tissue. Only one of two possible C‐24 epimeric alcohols appears to occur in human brain (V an L ier and S mith , 1970) and the sterol may be regarded as a true endogenous trace‐level sterol and not as an artifact of autoxidation derived during isolation and analysis. As a phase of our continuing interests in the presence of trace‐level polar sterols in human tissues (V an L ier and S mith , 1967 , 1969, 1970 , 1971a; S mith and V an L ier , 1970), we sought to measure levels of 24‐hydroxycholesterol in different parts of human brain by gas chromatographic means. The present report deals with our measurements of 24‐hydroxycholesterol in human cortex, subcortical white matter, midbrain, pons, and cerebellum.