Abstract: Based on the scientific phenomenon that cells in peripheral tissues can synthesize and respond to hormones (peptides, proteins or steroids), a new concept of endocrinology - "intracrinology" was first proposed in the late 19th century. Peripheral tissues such as endometrium can express various enzymes including STS, SULT1E1, CYP19A1, 17β-HSD, which utilize steroid precursors presenting in the blood to participate in the local synthesis and metabolism of steroid hormones (intracrinology). In the absence of progesterone antagonism, sustained stimulation of endometrium by locally synthesized estrogen is a high risk factor for the occurrence and development of endometrial cancer. Drugs targeting the local estrogen metabolism in the peripheral tissues, such as aromatase inhibitors, STS inhibitors and inhibitors of HSD17B1 can effectively reduce serum estrogen level and thus can be used as therapeutic agents against endometrial cancer. These drugs also have a certain effect on other estrogen-dependent diseases such as uterine leiomyoma, endometrial hyperplasia and endometriosis.

Key words: Intracrinology, Gonadal steroid hormones;, Endometrial neoplasms;, Molecular targeted therapy