What is it about?

We studied whether the IGFBP-3 gene polymorphism rs2854744 is associated with erectile dysfunction.

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Why is it important?

Erectile dysfunction (ED) is mostly a disease of vascular etiology. The pathophysiology of ED is a decrease in smooth muscle relaxation or an increase in contractile tone in the corpus cavernosum vasculature. The principal neurotransmitter responsible for cavernous smooth muscle relaxation and subsequent penile erection is nitric oxide (NO). NO synthase (NOS) synthesizes NO from L-arginine and oxygen, which then activates guanylyl cyclase to convert guanosine triphosphate into its active form, cyclic guanosine monophosphate. IGF-I has a crucial role in the regeneration of NOS containing nerve fibers in the dorsal and intracavernous nerves.3 Pu et al noted that intracavernous injection of IGF-I protein improved erectile function in aging rats by restoring the integrity of corpus cavernosum smooth muscle and the modulation of NO-cyclic guanosine monophosphate pathways.


It was suggested that IGF-I is a vital growth factor gene in ED. Possibly increased levels of IGFBP-3, which is known to have an important role in inhibiting IGF-I action, might be a factor predisposing to ED. IGF-I enhanced the regeneration of NOS containing penile nerves after neurotomy of cavernous nerves in rats. Soh et al reported that in diabetic rats increased IGFBP-3 expression occurs before the decrease in smooth muscle density and intracavernous pressure. Enhanced IGFBP-3 expression might limit the availability of IGF-I and, thus, result in the depletion of smooth muscle density and ED in diabetic patients. The beneficial effect of PDE-5 inhibitors correlates with the amount of NO in the field. Therefore, patients with ED and the IGFBP-3 CC genotype might have a better response to PDE-5 inhibitors.

Dr Mohammad Reza Safarinejad
University of Medical Sceices

Read the Original

This page is a summary of: The Influence of Promoter –202 A/C Polymorphism (rs2854744) of the IGFBP-3 Gene on Erectile Dysfunction Risk and Serum Levels of IGF-I and IGFBP-3, The Journal of Urology, January 2013, Wolters Kluwer Health, DOI: 10.1016/j.juro.2012.08.176.
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