Which two hormones are primarily responsible for lactation?

Prolactin and oxytocin are essential hormones involved in lactation. Prolactin is crucial for the production of milk in the mammary glands. It stimulates the cells in the breast to synthesize milk, making it the key hormone responsible for initiating and sustaining milk production after childbirth.

Oxytocin, on the other hand, plays a vital role in the actual process of milk ejection or let-down. When a baby suckles at the breast, oxytocin is released, causing the smooth muscles around the milk ducts to contract and expel milk. This tandem action allows for effective breastfeeding, with prolactin ensuring there is milk available and oxytocin facilitating its release during nursing.

The other hormone combinations listed do not have the direct dual role in lactation as prolactin and oxytocin do. While estrogen and progesterone are important during pregnancy for preparing the breast tissue for lactation, they do not have a role in milk production or ejection once lactation commences. Similarly, cortisol and levels of oxytocin may influence other bodily functions, but they do not specifically correlate with the lactation process as effectively as prolactin and oxytocin do together.