Occurrence of Desmosterol in Tumors of the Nervous System Induced in the Rat by Nitrosourea Derivatives1

Desmosterol (24-dehydrocholesterol), a precursor of cho lesterol, represents 5 to 20% of the total sterols of the brain during maturation, although it is practically absent in normal adult brain. The desmosterol content is increased to a small extent in human glial tumors and in some transplantable experimental tumors. In the present experiments it has been shown that desmo sterol accumulates in considerable amounts in experimen tal tumors of the nervous system obtained in Long-Evans rats either by i.v. administration of methylnitrosourea or by transplacental induction with ethylnitrosourea. The signifi cance of this finding is discussed.