Dihydrotestosterone inhibits murine hair growth via the androgen receptorA. Naito, T. Sato*, T. Matsumoto*, K. Takeyama*, T. Yoshino, S. Kato* and M. Ohdera
Biological Science Research Laboratories, Research and Development Headquarters, LION Corporation, 100 Tajima, Odawara, Kanagawa 256-0811, Japan
*Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Japan
Correspondence to A. Naito.
Conflicts of interest
Copyright Journal Compilation © 2008 British Association of Dermatologists
androgenetic alopecia • androgen receptor knockout mouse • hair cycle
Background Androgens cause regression of human hair follicles in the parietofrontal scalp, but the precise mechanisms by which they do so are unknown. Although many investigators have elucidated the effect of androgens on hair growth by using rodents and other animals, some of the evidence is conflicting.
Objectives To investigate the effect of androgens on mouse hair regrowth and hair cycle by using androgen receptor knockout (ARKO) mice.
Methods We examined the effects of dihydrotestosterone (DHT) on hair regrowth by using ARKO mice and wild-type (WT) littermates, compared the hair cycles in ARKO mice and WT littermates by histology and histomorphometry, and measured hair length and thickness in ARKO mice and WT littermates.
Results DHT inhibited the hair regrowth of WT mice but not that of their ARKO littermates. The anagen phase in the second hair cycle was longer in ARKO mice than in their WT littermates. The hair of ARKO mice was longer and thicker than that of their WT littermates.
Conclusions Androgens inhibit hair growth in mice, and this inhibition might be caused by androgen–androgen receptor signals.
The reason I posted this was simple…mice ARE A GOOD WAY TO TEST ANTI-ANDROGENS. I would expect finasteride/dutasteride to give some decent regrowth to ‘wild type’ mice or at least accelerate their growth. In a way, this is pretty good news, because potential topical anti-androgens like Pfizer’s or Androscience’s can be first tested on mice before bothering with the expense of testing them on people. Murine tests are much cheaper to perform than human tests. Hopefully, some entity will come up with a topical that not only blocks the receptor or inhibits alpha five reductase, but inhibits its expression so it does not mutate over time to accept other molecules and use them as androgens, etc.