Prolactin

Prolactin is a hormone produced in the pituitary gland, and plays a key role in fertility, reproduction, and the stimulation of breast milk production. It is also involved in regulating the immune system, suppressing the stress response, creating and activating new neurons, and stimulating motherly (maternal) behaviour. Men and non-pregnant women generally have low levels of prolactin. In women, prolactin tests help diagnose the causes of absent or irregular menstruation, spontaneous or abnormal breast milk flow or other unexplained discharges. In men, they can help diagnose erectile dysfunction or loss of sex drive (libido).