! Effect of androgen deprivation on penile ultrastructure

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#1

[Size=4]Effect of androgen deprivation on penile ultrastructure[/size]

[This is a must-read study for all of us! Be sure to look at the images – they show what happens to penile tissues when they are deprived of androgens via Finasteride or Castration — both produce very similar results.]

FULL TEXT:
asiaandro.com/archive/1008-682X/5/33.htm

ABSTRACT:

Aim:
To investigate the ultrastructural changes of penile corpus cavernosum and tunica albuginea in rats treated with castration or finasteride.

Methods:
Eighteen male Sprague-Dawley rats of nine weeks old were randomly divided into three groups with 6 rats each.

Group A served as the control, Group B was castrated and Group C, treated with finasteride.

Four weeks later, rats were anesthetized and blood samples obtained for the determination of serum testosterone (T) and dihydrotestosterone (DHT) levels; penile tissues were taken for scanning electron microscopy.

Results:
The T, free T and DHT levels in Group B and the DHT level in Group C were significantly lower than those in Group A (P<0.05).

The tunica albuginea was significantly thinner in Group B than that in Group A (P<0.05), but there was no significant difference between Group C and Group A (P>0.05).

Elastic fibers in the tunica albuginea of Group A were very rich and arranged regularly and undulatedly, but in Group B, most of the elastic fibers were replaced by collagenous fibers.

In Group C, the tunica albuginea was mainly composed of thick and irregular-arranged collagenous fibers.

In Group A, there were abundant smooth muscle fibers in the trabeculae of corpus cavernosum, but they were much less in Group C and scarce or even disappeared in Group B.

In Groups B and C, the diminished/disappeared smooth muscle fibers were replaced by irregularly arranged collagenous fibers.

Conclusion:
In rats, androgen is essential for maintaining the normal structure of penile tunica albuginea and corpus carvenosum.

#2

Corroboration of the above study. Below is a selected paragraph…

The Effect of 5 -Reductase Inhibitors on Erectile Function
From the Johns Hopkins Hospital, Baltimore, Maryland

Received for publication January 28, 2008; accepted for publication April 9, 2008.

andrologyjournal.org/cgi/con … l/29/5/514

"… Further evaluation of the role of DHT in the penis has been done at the penile morphologic level. Shen et al (2000) investigated the ultrastructural changes of the penile corpus cavernosum and tunica albuginea in rats representing 3 groups: sham control, castrated, and treated with finasteride. Four weeks later, blood samples were obtained for the determination of serum T and DHT levels, and penile tissues were taken for scanning electron microscopy.

The T and DHT levels in castrated rats and the DHT level in finasteride-treated groups were significantly lower than those in the control group.

In the castrated animals, there was a high degree of fibrosis in the corpus cavernosum with irregularly arranged collagenous fibers and a marked decrease in smooth muscle fibers, while in the DHT-inhibited group ([Size=4]finasteride-treated), the corpus cavernosum comprised a substantial amount of thick and irregularly arranged collagenous fibers[/size], but the degree of fibrosis was less than that of the castration group (Shen et al, 2000).

This work suggests that [Size=4]because finasteride inhibits the action of DHT but not T on the corporal cavernosal tissue, the degree of fibrosis was less in the DHT-inhibited group than in the castration group[/size].

In the castration group, the thickness of tunica albuginea decreased significantly and the elastic fibers were mostly supplanted by collagenous fibers, and [Size=4]in the DHT-inhibited group, the elastic fibers were replaced by disorganized and thick collagenous fibers[/size].

[Size=4]Since the tunica albuginea plays a major role in the erectile mechanism of the penis, the latter results offer an explanation for the presentation of ED in patients treated with 5ARIs[/size]."

"…T and DHT perform vital functions in various organs in different ratios. DHT is more active in prostate than T.

This may be due to the fact that DHT is largely a paracrine hormone and exerts effects in tissues of its origin. On the other hand, T is more relevant than DHT in erectile function, which requires central and peripheral androgenic activity. T exerts both humoral endocrine and local paracrine effects.

In this review, we summarized the effect of 5ARIs with respect to erectile function. It is likely that androgens are vital for the development, maintenance and function of penile tissue and regulation of erectile physiology.

However, the critical androgenic substance for these effects is most likely T rather than DHT. "