Scientific research has concluded that breast tissue growth occurs as a result of the effects of estrogen, progesterone, prolacin, prostaglandins, and human growth hormone. It is important that all of these hormones be present in the body in the proper balance for normal breast tissue development.
During childhood, estrogens are secreted in small quantities. Following puberty however, the quantity of estrogens secreted under the influence of the pituitary hormones (FHS, LH) increases some 20 fold or more.
At this time sexual organs change from those of a child to that of an adult. The external genitalia enlarge. Estrogens effect on the breast causes fat deposition, development of the stromal tissues of the breast and growth of an extensive ductile system. Along with estrogen, progesterone and prolactin are secreted in higher quantities from the ovaries after puberty. These two hormones are responsible for growth of the lobules and alveoli of the breast determining growth and function of these structures.