Hormonal Regulation of Hair Follicles Exhibits a Biological Paradox

February 2007 in “ Seminars in Cell & Developmental Biology ”

Valerie A. Randall

androgens hair follicles balding scalp hormones hair growth cycles anagen phase androgen receptor gene dermal papilla cells gene expression hair characteristics hair disorders androgen-dependent conditions hair growth hair loss baldness pregnancy hormones

TLDR Androgens can both stimulate and cause hair loss, and understanding their effects is key to treating hair disorders.

The document from 2007 examines the paradoxical effects of androgens on hair follicles, where they can stimulate hair growth in certain body areas while causing balding on the scalp. It discusses the role of hormones in hair growth cycles, with a study of 14 men showing seasonal variations in hair growth. The paper also explores how pregnancy hormones affect hair growth, with an increase in anagen phase during the second and third trimesters. The document emphasizes the importance of genetics in androgen-dependent hair growth, noting variations in the androgen receptor gene in balding men. It describes the current model of androgen action, where androgens act on dermal papilla cells, altering gene expression and affecting hair characteristics. The paper concludes that understanding the specific factors altered by androgens is crucial for developing treatments for hair disorders and provides insights into other androgen-dependent conditions.

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