Sulfation and desulfation of neuroactive steroids in normal and neoplastic primate brain tissues

A novel methodology for the determination of steroid sulfatase (STS) and sulfotransferase (SULT) activities in primate brain tissue have been developed and evaluated. STS activity determination was based on enzyme assay followed by liquid-liquid extraction ofthe reaction product, its subsequent derivatization and gas chromatography-mass spectrometry analysis. Indirect determination including product hydrolysis and determination by radioimmunoassay was used for assessment of SULT activity. For both, STS and SULT assays, optimal reaction conditions were found while strong structure-activity relationships for both enzyme activities were observed. Additionally, so far unidentified high-substrate inhibition for STS was revealed wíth a hypothesis suggesting its physiotogícal relevance' Determinations of STS and SULT activities in monkey brain regions revealed differences between genders and brain regions. Due to low number of samples, significance was not described. For STS kinetic characteristics were determined. In human brain tumors, STS and SULT activities showed highly significant differences according to diagnoses. Furthermore, tendency to cluster formation with respect to both enzyme activities emerged. It indicated specific metabolic characteristics especially for glioblastomas considered as the..