Sterol sulfate metabolism in the adrenals of the human fetus, anencephalic newborn, and adult.

The sulfurylation of pregnenolone (delta 5P), dehydroepiandrosterone (D) and cholesterol in subcellular fractions of the separated zones of normal human fetal adrenals as well as the mitochondrial sterol desmolase activities are investigated. The values obtained are compared to those found in adrenal tissues of anencephalics and adults. The 3 beta-hydroxysteroid sulfotransferase activity is localized principally in the cytosolic fraction of the tissues assayed. The highest rate of sulfurylation of delta 5P and D is found in the cytosol of the fetal zone (5 nmol min-1 mg protein-1). The corresponding activities in fetal neocortex, anencephalic, and adult adrenocortical tissues are one tenth of that in the fetal zone. Cholesterol sulfurylation is not detectable under similar assay conditions. The specific activities of cholesterol and cholesteryl sulfate desmolases are 3- 4-fold greater in the fetal zone than in the neocortex. Cholesterol desmolase activity, but not cholesteryl sulfate desmolase activity, is found in adrenal tissues of the anencephalic newborn and adult adrenal cortex. It is concluded that the high levels of delta 5P sulfate and D sulfate found in human fetal plasma arise not only as a consequence of the high capacity of the human fetal adrenal fetal zone to sulfurylate the unconjugated compounds, but also as a result of the conversion of cholesteryl sulfate to delta 5P sulfate and thence to D sulfate.