Q.Which hormone acts on the myoepithelial cells around the alveoli of the mammary gland to bring about milk ejection (the 'let-down' reflex)?

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Oxytocin contracts the myoepithelial cells around the mammary alveoli, actively ejecting stored milk …

Suckling by the infant sends sensory signals to the mother's hypothalamus, which triggers release of oxytocin from the posterior pituitary. Oxytocin acts on myoepithelial cells surrounding the milk-secreting alveoli and the ducts leading from them, causing these cells to contract and squeeze stored milk out toward the nipple -- the let-down r …

Separate the two lactation hormones by function: prolactin makes milk (synthesis); oxytocin releases milk alread …

Mixing up prolactin and oxytocin's roles -- prolactin is often (wrongly) credited with milk ejection because it is the more commonly named 'milk hormon …