Estrone and dehydroepiandrosterone sulfatase activities in normal and pathological human endometrium biopsies

The properties of estrone (E1) and dehydroepiandrosterone (DHEA) sulfatase activities are reported. Endometrial biopsy specimens were obtained using a Novak curette. Cycle stage was assessed from histological dating of endometrium, plasma estradiol and progesterone levels, and patient history. Both sulfatases are membrane-bound enzymes. The optimum pHs in Tris-HCl buffer were 6.5 for E1 sulfatase and 7.3 for DHEA sulfatase. Lowest activities and different optimum pHs were obtained with imidazole, maleate, or acetate buffers. DHEA sulfatase is more sensitive to thermal inactivation than E1 sulfatase. From kinetic studies, apparent Km values of 3.1 microM for E1 sulfatase and 5.7 microM for DHEA sulfatase were calculated. Noncompetitive inhibition of E1 sulfatase by DHEA sulfate and of DHEA sulfatase by E1 sulfate were demonstrated. The effects of inorganic ions and unconjugated steroids were also tested. These results are consistent with two different activities hydrolyzing E1 or DHEA sulfates. Neither activity varies during normal menstrual cycles nor is not correlated to plasma progesterone or 17 beta-estradiol levels. An isolated increase in E1 sulfatase occurred in the proliferative phase of irregular menstrual cycles, postantibiotic-treated salpingitis, or hyperplastic endometrium.