Editing Progesterone (section)

====Lobuloalveolar development====
Progesterone plays an important role in [[breast development]]. In conjunction with [[prolactin]], it mediates [[mammary alveolus|lobuloalveolar]] maturation of the [[mammary gland]]s during pregnancy to allow for milk production and thus [[lactation]] and [[breastfeeding]] of [[offspring]] following [[parturition]] (childbirth).<ref name="pmid22844349">{{cite journal | vauthors = Macias H, Hinck L | title = Mammary gland development | journal = Wiley Interdisciplinary Reviews. Developmental Biology | volume = 1 | issue = 4 | pages = 533–557 | year = 2012 | pmid = 22844349 | pmc = 3404495 | doi = 10.1002/wdev.35 }}</ref> [[Estrogen]] induces expression of the PR in breast tissue and hence progesterone is dependent on estrogen to mediate lobuloalveolar development.<ref name="pmid16917139" /><ref name="Johnson2003" /><ref name="CoadDunstall2011" /> It has been found that {{abbrlink|RANKL|Receptor activator of nuclear factor kappa-B ligand}} is a critical downstream mediator of progesterone-induced lobuloalveolar maturation.<ref name="pmid26266959">{{cite journal | vauthors = Hilton HN, Graham JD, Clarke CL | title = Minireview: Progesterone Regulation of Proliferation in the Normal Human Breast and in Breast Cancer: A Tale of Two Scenarios? | journal = Molecular Endocrinology | volume = 29 | issue = 9 | pages = 1230–1242 | date = September 2015 | pmid = 26266959 | pmc = 5414684 | doi = 10.1210/me.2015-1152 }}</ref> RANKL [[knockout mice]] show an almost identical mammary phenotype to PR knockout mice, including normal mammary ductal development but complete failure of the development of lobuloalveolar structures.<ref name="pmid26266959" />