Steroid sulphatase activity in the skin biopsies of various types of ichthyosis

Abstract

A simple method was developed for the determination of steroid sulfase activity in a skin biopsy. Six milligrams of minced tissue were incubated in 1 ml of Krebs-Ringer bicarbonate buffer with radioactive dehydroepiandrosterone sulfate (20,000 cpm, S.A. [specific activity] 1.1 Ci/mmol) for 4 h. After the incubation the liberated unconjugated dehydroepiandrosterone and its possible metabolites were separated from the conjugated compound by extraction with ethyl acetate-ethyl ether 10:90 (vol/vol). The organic phase was counted in a scintillation counter. The results are expressed as cpm values per 6 mg tissue wet wt. Steroid sulfatase activity was measured in skin biopsies from 9 control subjects and from 13 patients with various types of ichthyosis. The ranges of the cpm values were as follows: controls (n = 9), 377-1802; X-linked ichthyosis (n = 5), 140-214; ichthyosis vulgaris (n = 5), 607-1320; ichthyosiform erythroderma (n = 2), 2146-2214; lamellar ichthyosis (n = 1), 2185. The reagent blank varied from 180 to 259 cpm. In X-linked ichthyosis the cpm values were always less than in the corresponding reagent blank, indicating that no enzyme activity was present in the tissue. In other types of ichthyosis, steroid sulfatase activity was normal.