Suppression by prolactin of the electrically induced erectile response through its direct effect on the corpus cavernosum penis in the dog.
OBJECTIVE
Men become impotent when exposed to hyperprolactinemia. To clarify its mechanisms the effects of intracorporal infusion of prolactin on electrically induced penile erection were evaluated in 12 male dogs.


METHODS
Prolactin (10 micrograms./ml.) or control saline was directly infused into the corpus cavernosum penis 5 minutes before electrical pulse stimulation of the pelvic nerve and the intracorporal pressure was monitored.


RESULTS
In 8 dogs erection was markedly suppressed or completely abolished by prolactin. In the remaining 4, this effect of prolactin became manifest only when the ipsilateral internal pudenal artery was ligated. Saline infusion was without effect.


CONCLUSIONS
An excess of prolactin directly inhibited the smooth muscle relaxation of corpus cavernosum penis.
Aoki
H
H
Department of Urology, Iwate Medical University, School of Medicine, Japan.
Fujioka
T
T
Matsuzaka
J
J
Kubo
T
T
Nakamura
K
K
Yasuda
N
N
D000818:Animals; D001158:Arteries; D001794:Blood Pressure / Q000187:drug effects; D003250:Constriction; D004285:Dogs; D004558:Electric Stimulation; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D010410:Penile Erection / Q000187:drug effects*; D010413:Penis / Q000187:drug effects* / Q000502:physiology; D011388:Prolactin / Q000494:pharmacology*
D011388:Prolactin