KALLIKREINS AND KININS IN INFLAMMATORY-LIKE EVENTS IN THE REPRODUCTIVE-TRACT

The normal reproductive events of proliferation of the endometrial lin ing of the uterus during the menstrual cycle and ovulation have been l ikened to inflammatory-like events. The kallikrein-kinin system is inv olved in inflammatory processes in many tissues. In this review, we id entify which components of the kallikrein-kinin system - the enzyme, t issue kallikrein; the substrate, low molecular weight kininogen and th e effector receptor for the generated bradykinin peptide, the B2 recep tor - have been identified in the uterus and ovary and their known inv olvement in the function of these organs. All three components have be en localized to the glandular, epithelial cells of the human endometri um. Tissue kallikrein gene expression is elevated midcycle when estrog ens levels are also rising. This is also a time of extensive endometri al proliferation and tissue remodelling in preparation for embryo impl antation, an event which is likened to other inflammatory processes. S imilarly, tissue kallikrein gene expression was elevated following the estrogen surge at proestrous in the rat uterus, suggesting tissue kal likrein gene expression may be regulated by estrogens. Tissue kallikre in enzyme activity and gene expression has been demonstrated in the ra t ovary and shown to be variously altered at the time of ovulation. Br adykinin has also been implicated in the expulsion of the ovum at the time of ovulation. These findings show that various components of the kallikrein-kinin system are present in the uterus and ovary. Further s tudies are required to more fully delineate their role in reproductive function. (C) 1997 The Italian Pharmacological Society.