Androgen+Receptor

=The Androgen Receptor = = =

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To begin our understanding of the androgen receptor we must define what an androgen is. An androgen is a hormone (usually a steroid hormone) found in the body that is an important factor in the development of male sex differentiation in the womb or during puberty. Androgens include testosterone and dihydrotestosterone (DHT). When an androgen-androgen receptor complex is made it is able to bind DNA and silence or promote expression of androgen sensitive genes which lead to male primary and secondary sex traits. (1) ======

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Studies have shown that increased androgen levels (specifically DHT) and increased AR activity in the hair follicle are recorded in a balding scalp. (7) This causes premature entry into the Telogen phase of hair-follicle cycling and the thinning of hair. ======

= = //ishrs.org//. (n.d.). Retrieved from http://www.ishrs.org/hairloss-hair-loss-cycle.htm

--Anagen--
This is the active hair growth phase.

--Catagen--
This is a transition phase that signals the end of active hair growth.

--Telogen--
This is the resting phase (hair can fall out here or it will be pushed out by the new hair grown when returned to Anagen).

The androgen receptor is also associated with many other conditions including:

 * ======Androgen insensitivity syndrome ======
 * ======Breast cancer ======
 * ======Spinal and bulbar muscular atrophy ======

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(1)Androgenetic alopecia. (2006, May). Retrieved from http://ghr.nlm.nih.gov/condition/androgenetic-alopecia <span style="font-family: Arial,Helvetica,sans-serif;"> (7)Hillmer, A. M., Hanneken, S., Ritzmann, S., Becker, T., Freudenberg, J., Brockschmidt, F. F., Flaquer, A., Freudenberg-Hua, Y., Jamra, R. A., Metzen, C., Heyn, U., Schweiger, N., and 13 others. Genetic variation in the human androgen receptor gene is the major determinant of common early-onset androgenetic alopecia. Am. J. Hum. Genet. 77: 140-148, 2005.