HSD17B1 expression enhances estrogen signaling stimulated by the low active estrone, evidenced by an estrogen responsive element-driven reporter gene in vivo.

Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) belongs to a family of short-chain-dehydrogenases. The enzyme utilizes NAD(P) and NAD(P)H as cofactors, and catalyzes the reversible reaction between estrone (E1) and estradiol (E2) in vitro. Of these steroids, E1 presents with lower estrogenic activity, but is converted to highly active E2 by HSD17B1.

Intra-tissue steroid profiling indicates differential progesterone and testosterone metabolism in the endometrium and endometriosis lesions.

Context: Aberrant sex steroid signaling is suggested to promote endometriosis growth by several mechanisms, and the tissue concentrations of sex steroids are key determinants of the hormone action. However, their concentrations are only superficially known in the endometrium and endometriosis lesions.

Objective: This study sought to evaluate whether the tissue steroid hormone concentrations in endometriosis differ from the endometrium or serum.