Editing Estrogen (section)

====Breast development====
{{See also|Breast development#Biochemistry}}

Estrogen, in conjunction with [[growth hormone]] (GH) and its secretory product [[insulin-like growth factor 1]] (IGF-1), is critical in mediating breast development during [[puberty]], as well as breast maturation during [[pregnancy]] in preparation of [[lactation]] and [[breastfeeding]].<ref name="Malley2010">{{cite journal | vauthors = Brisken C, O'Malley B | title = Hormone action in the mammary gland | journal = Cold Spring Harbor Perspectives in Biology | volume = 2 | issue = 12 | pages = a003178 | date = December 2010 | pmid = 20739412 | pmc = 2982168 | doi = 10.1101/cshperspect.a003178 }}</ref><ref name="pmid9516076">{{cite journal | vauthors = Kleinberg DL | title = Role of IGF-I in normal mammary development | journal = Breast Cancer Research and Treatment | volume = 47 | issue = 3 | pages = 201–208 | date = February 1998 | pmid = 9516076 | doi = 10.1023/a:1005998832636 | s2cid = 30440069 }}</ref> Estrogen is primarily and directly responsible for inducing the ductal component of breast development,<ref name="Johnson2003">{{cite book | vauthors = Johnson LR | title = Essential Medical Physiology | url = https://books.google.com/books?id=j9e-tkdHeUoC&pg=PA770 | year = 2003 | publisher = Academic Press | isbn = 978-0-12-387584-6 | pages = 770 }}</ref><ref name="NormanHenry2014">{{cite book | vauthors = Norman AW, Henry HL | title = Hormones | url = https://books.google.com/books?id=_renonjXq68C&pg=PA311 | date = 30 July 2014|publisher=Academic Press | isbn = 978-0-08-091906-5 | pages = 311 }}</ref><ref name="CoadDunstall2011">{{cite book | vauthors = Coad J, Dunstall M | title = Anatomy and Physiology for Midwives, with Pageburst online access,3: Anatomy and Physiology for Midwives | url = https://books.google.com/books?id=OmSKoYD-iW0C&pg=PA413 | year = 2011 | publisher = Elsevier Health Sciences | isbn = 978-0-7020-3489-3 | pages = 413 }}</ref> as well as for causing [[fat deposition]] and [[connective tissue]] growth.<ref name="Johnson2003" /><ref name="NormanHenry2014" /> It is also indirectly involved in the lobuloalveolar component, by increasing [[progesterone receptor]] expression in the breasts<ref name="Johnson2003" /><ref name="CoadDunstall2011" /><ref name="HaslamOsuch2006">{{cite book | vauthors = Haslam SZ, Osuch JR | title = Hormones and Breast Cancer in Post-Menopausal Women | url = https://books.google.com/books?id=wGaKtDw50K0C&pg=PA69 | date = 1 January 2006 | publisher=IOS Press | isbn = 978-1-58603-653-9 | pages = 69 }}</ref> and by inducing the secretion of [[prolactin]].<ref name="SilbernaglDespopoulos2011">{{cite book | vauthors = Silbernagl S, Despopoulos A | title = Color Atlas of Physiology | url = https://books.google.com/books?id=WyuCGhv4kvwC&pg=PA305 | date = 1 January 2011 | publisher = Thieme | isbn = 978-3-13-149521-1 | pages = 305– }}</ref><ref name="Fadem2007">{{cite book| vauthors = Fadem B | title = High-yield Comprehensive USMLE Step 1 Review | url = https://books.google.com/books?id=d-MxROzDPgcC&pg=PA445 | year = 2007 | publisher = Lippincott Williams & Wilkins | isbn = 978-0-7817-7427-7 | pages = 445– }}</ref> Allowed for by estrogen, [[progesterone]] and prolactin work together to complete lobuloalveolar development during pregnancy.<ref name="NormanHenry2014" /><ref name="Blackburn2014">{{cite book | vauthors = Blackburn S | title = Maternal, Fetal, & Neonatal Physiology | url = https://books.google.com/books?id=RNLsAwAAQBAJ&pg=PA146 | date = 14 April 2014 | publisher = Elsevier Health Sciences | isbn = 978-0-323-29296-2 | pages = 146– }}</ref>

[[Androgen]]s such as testosterone powerfully oppose estrogen action in the breasts, such as by reducing [[estrogen receptor]] expression in them.<ref name="IIIBarbieri2013">{{cite book | vauthors = Strauss JF, Barbieri RL | title = Yen and Jaffe's Reproductive Endocrinology | url = https://books.google.com/books?id=KZ95AAAAQBAJ&pg=PA236 | date = 13 September 2013 | publisher=Elsevier Health Sciences | isbn = 978-1-4557-2758-2 | pages = 236– }}</ref><ref name="WilsonNizet2015">{{cite book | vauthors = Wilson CB, Nizet V, Maldonado Y, Remington JS, Klein JO | title = Remington and Klein's Infectious Diseases of the Fetus and Newborn Infant | url = https://books.google.com/books?id=VuZ1BwAAQBAJ&pg=PA190 | date = 24 February 2015 | publisher = Elsevier Health Sciences | isbn = 978-0-323-24147-2 | pages = 190– }}</ref>