Question

Discuss hormonal interactions in the development of breasts and milk production.

Answer 1

• Development of breast and milk production is under the control of progesterone, estrogen, growth hormone and prolactin.
  
• When the ovaries start to produce and release (secrete) estrogen, fat in the connective tissue starts to collect. This causes the breasts to enlarge. The duct system also starts to grow. Once ovulation and menstruation begin, the maturing of the breasts begins with the formation of secretory glands at the end of the milk ducts. The breasts and duct system continue to grow and mature, with the development of many glands and lobules. Estrogen controls the growth of the ducts, and progesterone controls the growth of the glandular buds.
  
• During pregnancy, pronounced breast growth and maturation occurs in preparation of lactation and breastfeeding. Estrogen and progesterone levels increase dramatically, reaching levels by late pregnancy that are several hundred-fold higher than usual menstrual cycle levels. Estrogen and progesterone cause the secretion of high levels of prolactin from the anterior pituitary, which promotes milk production.