Testosterone metabolism in rat skin shows a cyclic behavior in relation to the hair growth phases. The possibility that castration could influence the activities of 17 beta, 3 alpha, 3 beta hydroxydehydrogenase (HDH), and of 5 alpha reductase suggested the study. The second hair cycle was induced by plucking normal or prepubertally castrated male rats. Testosterone 4 14C metabolism as well as DNA skin content were evaluated. 5 Alpha reductase activity normally increases in the first part of anagen, declines in advanced anagen and catagen, and goes up again in telogen. In castrated rats, these fluctuations occur at a higher level in telogen, whereas the rate of decrease in advanced anagen and catagen is reduced. 3 Alpha and 3 beta HDH behave like 5 alpha reductase. 17 Beta HDH remains in normal ranges for all animals. Thus the importance of pituitary tropins for the hair cycle is indicated, when gonadal hypophysis feedback is lacking, by the increasing activity of 5 alpha reductase, 3 alpha and 3 beta HDH.
|Number of pages||1|
|Journal||Journal of Investigative Dermatology|
|Publication status||Published - 1975|
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