Female hormone system. 2 of 2. Diagram showing the female endocrine system working to create the feeling of bonding in relationship. When a person falls in love, dopamine, norepinephrine and serotonin are released during the attraction phase. High levels of oestrogen (green spot on right ovary) are released during the lustful stage. During the long-term bonding stage afterwards, oxytocin is released from the brain's hypothalamus, which is triggered by orgasm responses during intercourse. The simultaneous release of vasopressin (orange spot) and endorphins (blue spot) from the pituitary gland also induce monogamy. See P750/171 for the hormone system involved in falling in love.