Studies on neurosteroids XII.: Determination of enzymatically formed catechol estrogens and guaiacol estrogens by rat brains using liquid chromatography–mass spectrometry–mass spectrometry

Enzymic formations of catechol- and guaiacol-estrogens by rat brains have been investigated using classical- and catechol-estrogens as substrates, respectively. The incubation mixtures were pretreated with liquid–liquid and/or solid-phase extraction, and the products were identified by comparison with authentic samples using liquid chromatography–mass spectrometry (–mass spectrometry) {LC–MS (–MS)}. The enzymic activities were also determined by measuring the formed products with LC–MS.