So I’ve been re-touching up on the subject of finasteride.
I find it funny that finasteride has been proven to cause the downregulation of NOS which causes subsequent effect on blood flow due to lack of cGMP activity for vasodialation.
E.D. in older men is a result of reduced oxygen tension which might be linked (in my opinion) to the expression of Nitric oxide synthase as the body ages. Since older men have a lower level of testosterone and DHT it seems likely that this reduction in hormones which have been shown in rats to support penile ultrastructure and reduce the collagenation of the penile tissue might cause a higher collagenation ratio which results in the replacement of smooth muscle with collagen fibers.
What I think is happening is that the reduction of expression in the enzymes which seems to support blood flow in the penile tissue (Nitric Oxide synthase) might cause fibrosis of the smooth muscle tissue resulting in an inability to produce erection even when exposed to drugs like PDE5 inhibitors or prostaglandin injections.
This disorder of high collagen ratio is treatable by prolonged usage of L-Arg. and also PDE5 inhibitors like caffeine and guarana (I wouldnt use Cialis or Viagra as they have affinity for PDE6 which may cause problems with your eyes if you use them for a prolonged period of time.)
It seems likely also that there may be some chemical imbalance caused by this reduction in gene expression which may be due to the fact of environmental stressors.
Meaning, if you have a high amount of epinephrine and corticosteroids (corisol has been linked with clinical depression) and a low amount of cGMP in your tissue then it seems likely that this may very well be the cause of loss of blood flow. (Note: cortisol has been linked to suppression of HGH, a primary hormone responsible for promoting healing in the body)
Just a thought, It might explain why older men who take proscar have an increased amount of sexual side effects than younger men, since from what I have read proscar and propecia reduce serum DHT levels by the same percentile in older and younger men. The only difference between proscar and propecia is bioavailibility and how long it takes to get eliminated from your system due to the higher dosage.
One thing I found interesting also is that finasteride, from what I have read forms a stable enzyme complex with 5aR causing inhibition of the enzyme for an extended period of time. So really, if the enzyme complex gets formed either way then why would 5mg and 1mg be any different as far as effect on 5aR and length of inhibition of the enzyme.
Just some thoughts.