Steroid sulfatase activity in leukocytes: A comparative study in 45,X; 46,Xi(Xq) and carriers of steroid sulfatase deficiency

The enzyme steroid sulfatase (STS) hydrolyses 3-beta-hydroxysteroid sulfate s. The female-male STS activity ratio is 1.04-1.7:1 in several cell lines i n adults and reaches 2:1 in prepubertal subjects, In fibroblasts, STS value s in X-chromosome abnormalities show a partial positive correlation accordi ng to the number of X-chromosomes. X-linked ichthyosis (XLI) carriers, with only one copy of the STS gene, present lower STS levels than normal contro ls. This study analyzes the STS activity in leukocytes of 46,Xi(Xq), 45,X; XLI carriers and normal controls using 7-[H-3]-dehydroepiandrosterone sulfa te as substrate. X-monosomy (1.07+/-0.18 pmol/mg protein/h), Xq isochromoso me (1.02+/-0.12 pmol/mg protein/h) and normal females (1.03+/-0.11 pmol/mg protein/h) had similar STS values (p>0.05). XLI-carriers and males showed t he lowest STS levels (0.34+/-0.04 pmol/mg protein/h, p<0.001 and 0.82+/-0.1 4 pmol/mg protein/h, p<0.05, respectively). Female-male STS activity ratio in leukocytes was 1.3:1. These data indicate that a complex mechanism regul ates the STS expression depending on each type of cell line.