Major Steroid and Peptide Hormonal Influences on the Breast (Adapted from Mccarty and Nath (8))

8. McCarty KS, Nath M. Breast. In: Sternberg SS, ed. Histology for Pathologists. Philadelphia: Lippincott-Raven; 1997:71–82.

Hormone Effects Estrogen Required for ductal growth and branching during adolescence Required for lobuloalveolar growth during pregnancy Required for induction of progesterone receptor Not necessary for maintenance of secretion or lactation Progesterone Required for lobuloalveolar differentiation and growth Probable mitogen in normal estrogenprimed breast Not necessary for ductal growth and branching Testosterone Stimulates breast mesenchyme during fetal development Causes mesenchymal destruction of mammary epithelium during critical period of testosterone sensitivity Glucocorticoids Required for maximal ductal growth Enhances lobuloalveolar growth during pregnancy Insulin Enhanced ductal-alveolar growth Enhances protein synthesis in mammary epithelium Required for secretory activity (with glucocorticoids and prolactin) Prolactin Stimulates epithelial growth after parturition Required for initiation and maintenance of lactation Human placental lactogen Able to substitute for prolactin in epithelial growth and differentiation Stimulates alveolar growth and lactogenesis in second half of pregnancy Growth hormone Required for ductal growth and branching during adolescence May contribute to lobuloacinar growth during pregnancy Thyroid hormone Increases epithelial response to prolactin May enhance lobuloacinar growth