Analysis of Neurosteroids

Abstract

The term neurosteroids applies to those steroids that are both synthesized in the nervous system, either de novo from cholesterol or from steroid hormone precursors, and that accumulate in the nervous system to levels that are at least in part independent of steroidogenic gland secretion rates. Neurosteroids consist of 17-or 20-oxosteroids and accumulate in the brain as unconjugated form and their sulfates, fatty acid esters and sulfolipids. The characterization and determination of neurosteroids including conjugates in the brain are summarized in this review. For example, the separation and characterization of 3-fatty acid esters (stearate, palmitate) of pregnenolone and dehydroepiandrosterone in the rat brain are carried out using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) operating in the positive-ion mode. The fatty acid esters obtained from the rat brain were derivatized with O-methylhydroxylamine to give the respective methyloximes, which were identified in comparison with their chromatographic behavior with authentic samples during LC/APCI-MS. The function of the steroids are also briefly described.