Activity of sterol-sulphate sulphohydrolase in rat brain: characterization, localization and change with age

Abstract— Homogenates of rat brain hydrolysed the sulphate esters of dehydroepiandrosterone, oestrone and pregnenolone to free steroids. The pH optimum was 6.6 for all three steroid sulphates. Under similar conditions, cholesterol sulphate was not hydrolysed to a significant extent. Unlike sterol sulphatases (EC 3.1.6.2) from extraneural tissues, most of the activity in brain was found in the crude nuclear fraction. The remainder of the activity was found in the crude mitochondrial fraction and almost none was detected in microsomal or cytosol fractions. Sterol sulphatase activity was present in the foetal brain and increased rapidly with increasing postnatal age to a plateau at approx. 25 days of postnatal age. The enzymic activity did not differ significantly with the sex of the animal. The sulphatase activity was found throughout the brain, with cerebellum and brain stem exhibiting a slightly higher activity per wet wt. of tissue than other regions. Inhibition of enzymic activity occurred in the presence of sodium deoxycholate, Triton X-100, sodium dodecyl sulphate and inorganic phosphate or sulphate.