Metabolism of dehydroepiandrosterone sulfate and estrone-sulfate by human platelets.

The aim of the present research was to study the uptake of DHEAS, and to establish the intracrine capacity of human platelets to produce sex steroid hormones. The DHEAS transport was evaluated through the uptake of [(3)H]-DHEAS in the presence or absence of different substrates through the organic anion transporting polypeptide (OATP) family. The activity of sulfatase enzyme was evaluated, and the metabolism of DHEAS was measured by the conversion of [(3)H]-DHEAS to [(3)H]-androstenedione, [(3)H]-testosterone, [(3)H]-estrone and [(3)H]-17beta-estradiol. Results indicated the existence in the plasma membrane of an OATP with high affinity for DHEAS and estrone sulphate (E(1)S). The platelets showed the capacity to convert DHEAS to active DHEA by the steroid-sulfatase activity. The cells resulted to be a potential site for androgens production, since they have the capacity to produce androstenedione and testosterone; in addition, they reduced [(3)H]-estrone to [(3)H]-17beta-estradiol. This is the first demonstration that human platelets are able to import DHEAS and E(1)S using the OATP family and to convert DHEAS to active DHEA, and to transform E(1)S to 17beta-estradiol.