Physiological and pathological roles of locally expressed kisspeptin and KISS1R in the endometrium.

Kisspeptins, encoded by the KISS1 gene, are a family of polypeptides that bind the kisspeptin receptor (KISS1R) to perform biological functions. Produced mainly in the hypothalamus, these neuropeptides regulate the pulsatile secretion of GnRH and trigger the hypothalamus-pituitary-gonadal axis. Other peripheral organs also express kisspeptin, which inhibits metastasis. Kisspeptin and KISS1R are reportedly present in the endometrium and may play roles in limiting the migration and invasion of trophoblasts into the endometrium during pregnancy (decidua) to maintain endometrial homeostasis. A deficiency of kisspeptin and KISS1R in the endometrium can lead to pathological conditions such as endometriosis and endometrial carcinoma. Kisspeptin and KISS1R in the endometrium can also promote endometrial receptivity and decidualization. Overall, kisspeptin and KISS1R are important for maintaining the normal physiological functions of the endometrium. By summarizing the roles of kisspeptin and KISS1R in the endometrium, our review explores the regulatory roles in the peripheral reproductive system of this peptide family that plays broad and profound roles in many physiological processes.