Editing Androgen (section)

===Male prenatal development===

====Testes formation====
During mammalian development, the gonads are at first capable of becoming either [[ovary|ovaries]] or testes.<ref>{{Cite book  |year=2000 |title=Developmental Biology |publisher=[[Sinauer Associates]] |location=[[Sunderland, Massachusetts]] |edition=6th |isbn=978-0-87893-243-6 |url=https://archive.org/details/developmentalbio00gilb | vauthors = Gilbert SF |url-access=registration }}{{Page needed|date=September 2010}}</ref> In humans, starting at about week 4, the gonadal rudiments are present within the [[intermediate mesoderm]] adjacent to the developing kidneys. At about week 6, epithelial [[sex cords]] develop within the forming testes and incorporate the [[germ cell]]s as they migrate into the gonads. In males, certain [[Y chromosome]] genes, particularly [[SRY]], control development of the male phenotype, including conversion of the early bipotential gonad into testes. In males, the sex cords fully invade the developing gonads.

====Androgen production====
The mesoderm-derived [[Epithelium|epithelial]] cells of the sex cords in developing testes become the [[Sertoli cell]]s, which will function to support sperm cell formation. A minor population of nonepithelial cells appear between the tubules by week 8 of human fetal development. These are [[Leydig cell]]s. Soon after they differentiate, Leydig cells begin to produce androgens.

====Androgen effects====
The androgens function as [[Paracrine signalling|paracrine]] [[hormone]]s required by the Sertoli cells to support sperm production. They are also required for the masculinization of the developing male fetus (including penis and scrotum formation). Under the influence of androgens, remnants of the [[mesonephron]], the [[Wolffian ducts]], develop into the [[epididymis]], [[vas deferens]] and [[seminal vesicles]]. This action of androgens is supported by a hormone from Sertoli cells, Müllerian inhibitory hormone (MIH), which prevents the embryonic Müllerian ducts from developing into fallopian tubes and other female reproductive tract tissues in male embryos. MIH and androgens cooperate to allow for movement of testes into the scrotum.

====Early regulation====
Before the production of the pituitary hormone [[luteinizing hormone]] (LH) by the embryo starting at about weeks 11–12, [[human chorionic gonadotrophin]] (hCG) promotes the differentiation of Leydig cells and their production of androgens at week 8.  Androgen action in target tissues often involves conversion of testosterone to 5α-[[dihydrotestosterone]] (DHT).