Which hormone stimulates milk production in the breasts during lactation?

Norepinephrine is a neurotransmitter and hormone primarily involved in the body's fight-or-flight response. It plays a role in increasing heart rate and blood flow but has no direct involvement in the stimulation of milk production. Thus, it does not affect lactation.

Antidiuretic hormone (ADH), also known as vasopressin, regulates water balance in the body by increasing water reabsorption in the kidneys. While it plays a crucial role in fluid regulation, it does not have any influence on milk production during lactation.

Oxytocin is involved in the milk ejection reflex, helping to release milk from the alveoli into the ducts during breastfeeding. However, while it is important for the milk let-down process, it does not stimulate the production of milk itself, which is the primary role of prolactin.