What hormone is secreted by the anterior pituitary gland and stimulates milk protein synthesis during pregnancy?

The secretion of prolactin from the anterior pituitary gland plays a crucial role during pregnancy, particularly in the synthesis of milk proteins. As pregnancy progresses, prolactin levels rise, which is essential for the development of the mammary glands and the preparation of breast tissue for lactation. Prolactin stimulates the alveolar cells in the breasts to produce milk, specifically promoting the synthesis of milk proteins such as casein and whey proteins.

This hormonal action is vital for successful breastfeeding after delivery, as it ensures that the mother will have adequate milk supply for her newborn. The increase in prolactin is influenced by several factors, including the presence of estrogen and progesterone, which also support pregnancy but do not directly stimulate milk protein synthesis.

Understanding the distinct roles of these hormones is important for grasping the physiological changes that occur during pregnancy and the preparations for postpartum breastfeeding.