Figure 4
From: The role of melatonin as an antioxidant in the follicle

Schematic representation of the presumed roles of melatonin in ovarian antral follicle. Melatonin, secreted by pineal gland, is taken up into the follicular fluid from the blood. ROS produced within the follicles, especially ovulation process, were scavenged by melatonin, and reduced oxidative stress may be involved in oocyte maturation and embryo development.