Development of the external genitalia: Perspectives from the spotted hyena (Crocuta crocuta)

This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-l...

Full description

Saved in:

Bibliographic Details
Published in:	Differentiation (London) Vol. 87; no. 1-2; pp. 4 - 22
Main Authors:	Cunha, Gerald R., Risbridger, Gail, Wang, Hong, Place, Ned J., Grumbach, Mel, Cunha, Tristan J., Weldele, Mary, Conley, Al J., Barcellos, Dale, Agarwal, Sanjana, Bhargava, Argun, Drea, Christine, Hammond, Geoffrey L., Siiteri, Penti, Coscia, Elizabeth M., McPhaul, Michael J., Baskin, Laurence S., Glickman, Stephen E.
Format:	Journal Article
Language:	English
Published:	England Elsevier B.V 01-01-2014
Subjects:	Androgens Androgens - metabolism Animals Clitoris Clitoris - growth & development Estrogens Estrogens - metabolism Female Genitalia, Female - growth & development Hyaenidae - genetics Hyaenidae - growth & development Hyena Male Ovary - growth & development Penis Penis - growth & development Testis - growth & development Urogenital sinus UGS 3DR IHC GEB Estrogens Hyena HUGE RIA E1 GT E2 DHT AR Clitoris Androgens T Penis ExG ER, ERα or ERβ Urogenital sinus AMH
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-like clitoris. Our studies indicate that early formation of the phallus in both males and females is independent of androgens; indeed the phallus forms before the fetal testes or ovaries are capable of synthesizing androgens. Likewise, pre- and postnatal growth in length of the penis and clitoris is minimally affected by “androgen status”. Nonetheless, several internal morphologies, as well as external surface features of the phallus, are androgen-dependent and thus account for dimorphism between the penis and clitoris. Finally, estrogens play a critical role in penile and clitoral development, specifying the position of the urethral orifice, determining elasticity of the urethral meatus, and facilitating epithelial–epithelial fusion events required for proper formation of the distal urethra/urogenital sinus and prepuce. Accordingly, prenatal inhibition of estrogen synthesis via administration of letrozole (an aromatase inhibitor) leads to malformations of the glans as well as the prepuce (hypospadias). The effects of prenatal androgens, anti-androgens and impaired estrogen synthesis correlated with the tissue expression of androgen and estrogen receptors. •Female spotted hyenas mate and give birth thru a penis-like clitoris.•Formation of male and female external genitalia (ExG) is androgen-independent.•Growth of male and female ExG is androgen-independent.•Sexual dimorphism in ExG is regulated by androgens and estrogens.•Estrogens appear to be involved in epithelial–epithelia fusion.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-3 content type line 23 ObjectType-Review-2
ISSN:	0301-4681 1432-0436
DOI:	10.1016/j.diff.2013.12.003