Progesterone Induction of 17β-Hydroxysteroid Dehydrogenase Type 2 during the Secretory Phase Occurs in the Endometrium of Estrogen-Dependent Benign Diseases But Not in Normal Endometrium

In the human endometrium, inactivation of 17β-estradiol to estrone is catalyzed by 17β-hydroxysteroid dehydrogenase type 2 (17βHSD2). Previous studies have shown that the 17βHSD2 activity in the endometrium is elevated during the secretory phase, as compared with the level during the proliferative phase, and that the elevation is in response to progesterone via the progesterone receptors. Recently, it has been demonstrated that aromatase cytochrome P450, the enzyme responsible for estrogen biosynthesis, is not present in the endometrium obtained from normal menstruating women with cervical cancer in situ showing no other gynecological disease (defined as “disease free”), but present in the endometrium obtained from patients with endometriosis, adenomyosis, and/or leiomyomas (defined as “diseased”). However, the previous 17βHSD studies have been performed without distinguishing between disease-free and diseased endometria. We, therefore, analyzed 17βHSD2 distinguishing between disease-free and diseased end...