Abstract

Purpose: The reduced circulating levels of dehydroepiandrosterone sulphate (DHEA-S) are associated with women with poor ovarian response, > 35 years old and low ovarian reserve (POSEIDON group 4, PG4) in cycles of controlled ovarian hyperstimulation. In the ovary, the uptake of DHEA-S is facilitated by the transmembrane organic anion-transporting polypeptide, OATP2B1, whereas in the cytoplasm, the hydrolysis of the inactive precursor DHEA-S into the biologically active steroid DHEA is catalyzed by the steroid sulfatase enzyme (STS). The objective of the present study was to evaluate DHEA and DHEA-S in serum and follicular fluid as well as the expression levels for STS and OATP2B1 in granulosa cells from women in PG4 compared to a control group (control) of age matched women with normal ovarian reserve and response to controlled ovarian hyperstimulation. Methods: Prospective study which included 23 women who underwent in vitro fertilization. We compared women in PG4 (n = 13) with a control (n = 8). Transcript levels and the cellular distribution of STS and OATP2B1 transporter were determined by qPCR and immunofluorescence respectively in granulosa cells collected at the time of oocyte pick-up. Gene expression was analyzed according to age, circulating AMH, antral follicle count (AFC) along with DHEA-S and DHEA in serum and follicular fluid. Results: Serum and follicular fluid analysis showed that DHEA-S was significantly decreased in PG4 compared to control, whereas no differences in DHEA concentrations were observed. Women in PG4 had significantly higher expression of STS and OATP2B1 mRNA (n = 13, p < 0.05) compared with those of the control. Conclusion: Our results suggest that up-regulation of STS and OATP2B1 in granulosa cells from women in PG4 could be a compensatory mechanism to overcome the decreased circulating levels of DHEA-S possibly required as substrate for intraovarian production of DHEA. © 2025 Elsevier Inc.