Analysis of testosterone effects on sonic hedgehog signaling in juvenile, adolescent and adult sprague dawley rat penis.
BACKGROUND
Smooth muscle apoptosis is a major contributing factor to erectile dysfunction (ED) development in prostatectomy and diabetic patients and animal models. A critical regulator of penile smooth muscle and apoptosis is Sonic hedgehog (SHH). The SHH protein is decreased in ED models and SHH treatment of cavernous nerve (CN) injured rats prevents smooth muscle apoptosis. A close association between androgen deficiency and ED has been suggested in the literature, but few studies have examined the molecular effects on penile smooth muscle and on known signaling mechanisms that regulate morphology. Aim. Examine testosterone and SHH interaction in eugonadal adult, adolescent and juvenile rats by performing castration studies and treatment with supraphysiological testosterone.


METHODS
The eugonadal adult Sprague Dawley rats were either treated with testosterone for 7 or 14 days (N = 14) or were castrated for 4 or 7 days (N = 12). The juvenile rats were treated with testosterone for 8 days (N = 7). The adolescent rats were castrated and sacrificed at P88 (N = 8). The control rats had empty vehicle (N = 22) or sham surgery (N = 20).


METHODS
The active form of SHH protein and mRNA were quantified by semi-quantitative immunohistochemical analysis and real-time reverse transcriptase polymerase chain reaction (RT-PCR).


RESULTS
Testosterone treatment did not alter SHH signaling in juvenile rats. Shh mRNA increased 3.2-fold and SHH protein increased 1.2-fold in rats castrated during puberty. In adult rats, castration decreased Shh mRNA 3.2-fold but did not alter SHH protein. Testosterone supplement in adult rats increased Shh mRNA 2.3-fold and decreased SHH protein 1.3-fold.


CONCLUSIONS
SHH signaling is independent of testosterone in normal juvenile rats and is sensitive to testosterone during adolescence, while testosterone supplement in the adult adversely impacts SHH signaling in a very similar manner to that observed with CN injury.
Bond
Christopher W
CW
Department of Urology, Northwestern University Medical School, Chicago, IL 60611, USA.
Angeloni
Nicholas L
NL
Podlasek
Carol A
CA
D000367:Age Factors; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D007172:Erectile Dysfunction / Q000378:metabolism / Q000503:physiopathology; D053823:Hedgehog Proteins / Q000096:biosynthesis / Q000378:metabolism*; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism / Q000503:physiopathology; D010413:Penis / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology*
D053823:Hedgehog Proteins; C546888:Shh protein, rat; D013739:Testosterone