Regulation of endometrial prostaglandins during the menstrual cycle and in early pregnancy

Prostaglandins are important regulators of endometrial function. In turn, their secretion is controlled by endocrine and paracrine mediators. Cyclical effects of ovarian oestrogen and progesterone throughout the menstrual or oestrous cycle result in overall higher levels of prostaglandin release during the secretory or luteal phase of the cycle than during the proliferative phase. Potential paracrine regulators of endometrial origin include cytokines, growth factors and histamine, some of which may arise from infiltrating cells. Embryo-derived factors can regulate endometrial prostaglandin release in early pregnancy. Both platelet-activating factor and ovine trophoblast protein-1 (an embryonic interferon) modify prostaglandin release from primary cultures of endometrial cells of human and ovine origin respectively. Manipulation of such mediators may provide new means for fertility control.