The corpus cavernosum produces and secretes physiologically relevant amounts of Ang II. The rate of Ang II secretion can be modulated by pharmacologic agents that regulate cytosolic calcium levels and are used clinically to treat erectile dysfunction. Intracavernosal injection of Ang II causes contraction of cavernosal smooth muscle and terminates spontaneous erection in anesthetized dog, while administration of an Ang II receptor antagonist results in smooth muscle relaxation and thus erection.

The corpus cavernosum produces and secretes physiologically relevant amounts of Ang II. The rate of Ang II secretion can be modulated by pharmacologic agents that regulate cytosolic calcium levels and are used clinically to treat erectile dysfunction. Intracavernosal injection of Ang II causes contraction of cavernosal smooth muscle and terminates spontaneous erection in anesthetized dog, while administration of an Ang II receptor antagonist results in smooth muscle relaxation and thus erection.

Sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, has become a first-line therapy for diabetic patients with erectile dysfunction (ED). The efficacy in this subgroup, based on the Global Efficacy Question, is 56% vs 84% in a selected group of non-diabetic men with ED. Two novel PDE5 inhibitors, tadalafil (Lilly ICOS) and vardenafil (Bayer), have recently completed efficacy and safety clinical trials in 'general' and diabetic study populations and are now candidates for US FDA approval. A summary analysis of the phase three clinical trials of sildenafil, tadalafil and vardenafil in both study populations is presented to provide a foundation on which the evaluation of the role of the individual PDE5 inhibitors for the treatment of patients with ED and DM can be built.

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