Hormone Signaling Pathways in the Postnatal Mammary Gland

Abstract

The mammary gland is an organ that in female mammals develops after birth and specializes to produce milk to feed the offspring. The mammary gland undergoes continued remodeling in response to hormonal cues that direct its development and function throughout sexual development and reproductive age. This gland can undergo numerous cycles of proliferation, differentiation and apoptosis after each pregnancy. This is accomplished by mammary stem cells (MaSCs) capable of sustaining continuous remodeling of the mammary tissue. The biological processes that regulate mammary morphogenesis and remodeling are regulated by steroid and peptide hormones which tightly control gene expression and epigenetic changes. This chapter aims to give a general overview of the main hormones and signaling pathways that control the female mammary gland differentiation leading to a fully functional milk producing gland. For this purpose, a summary of findings from commonly used cell and animal models, as well as humans was selected to explain the effects exerted by the main hormones implicated in mammary gland biology.