Does inhibition of 5AR II cause an increase of 5AR I?

[hairrific]

Shouldn't inhibition of 5AR type II enzyme with finasteride cause an increase of 5AR type I enzyme?

If not why not?

 

[Bryan]

I have a very interesting study by Happle and Hoffmann (my favorite hairloss researchers) that measured levels of 5a-reductase type I and type II mRNA in cultured human scalp hair follicles, in response to androgenic stimulation (they added extra testosterone). They found that type II mRNA was increased by the testosterone, but the type I mRNA was insignificantly affected. The obvious implication is that the type I enzyme isn't affected by androgenic stimulation, so I wouldn't expect finasteride to have any effect on its production.

 

[hairrific]

Thanks. And happy new year! unk: