Chronic renal failure causes wide-ranging disturbances in male erectile fun
ction, and the dysfunction usually is not corrected by hemodialysis, In thi
s study, erectile function and expression of nitric oxide synthase (NOS) is
oforms, insulin-like growth factor-I (IGF-I), and IGF-I binding proteins we
re assessed in rats in which uremia had been produced by 5/6 nephrectomy, I
n the animals that suffered renal failure, there was a significantly lower
rise in intracavernosal pressure in response to electrical stimulation, and
the mean patency period after cavernous nerve stimulation was significantl
y increased. The amount of neuronial NOS mRNA was significantly higher in t
he penile tissues and major pelvic ganglia (MPG) of uremic rats than in con
trol animals. There consistently were higher levels of nNOS and endothelial
NOS in the penile tissues and MPG of rats with renal failure, and there wa
s a significant decrease in the amount of IGF-I gene expression in the MPG
of these animals. Expression of the IGF binding proteins 2 and 4 but not 5
also was reduced. This preliminary work demonstrates that impairment of ere
ction in chronic renal failure in the rat is attributable to a disturbance
in NOS gene expression with concomitant changes in IGF-I, These discoveries
may permit an improved therapeutic approach to men with erectile dysfuncti
on associated with chronic renal failure.