European Journal of Dermatology. Volume 11, Number 4, 293-5, July – August 2001, Articles de la revue
Author( : S. Andersson,
The gonadal synthesis of testosterone from cholesterol involves cytochrome P-450 side-chain cleavage enzyme, cytochrome P-450 17a-hydroxylase, 3b-hydroxysteroid dehydrogenase, and 17b-hydroxysteroid dehydrogenase. A significant part of testosterone is converted in androgen target tissues to the more potent androgen dihydrotestosterone by the steroid 5a-reductase isoenzymes. Dihydrotestosterone, which binds to the nuclear androgen receptor with much greater affinity than testosterone, is the androgen responsible for male pattern hair loss. Consequently, the 5a-reductase inhibitor finasteride was developed and has proven efficacious in promoting hair regrowth. Likewise, C19-steroids produced by glandular and peripheral tissues may also feed into skin production of dihydrotestosterone, oxidative 3a-hydroxysteroid dehydrogenase, and 3b-hydroxysteroid dehydrogenase enzymes. Aberrant expression of one or more of these enzymes could conceivably result in increased scalp dihydrotestosterone levels, acceleration of the balding process in men and women.