What is the action of alprostadil in the treatment of erectile dysfunction?

Alprostadil is a prostaglandin E1 analog that plays a crucial role in treating erectile dysfunction. Its primary action is to enhance blood flow to tissues, particularly by inducing vasodilation. This occurs through the stimulation of specific receptors that lead to increased levels of cyclic adenosine monophosphate (cAMP), which results in smooth muscle relaxation and vasodilation in the penile arteries.

As blood vessels dilate, more blood can flow into the erectile tissues, facilitating an erection. This mechanism makes alprostadil a viable option for patients who may not respond to oral phosphodiesterase type 5 (PDE5) inhibitors, as it directly addresses the issue of inadequate blood flow that is critical for achieving and maintaining an erection.

The other options focus on actions that are not related to alprostadil's mechanism of action in treating erectile dysfunction. Increasing insulin sensitivity and promoting cGMP breakdown are unrelated pharmacological actions, and causing vasoconstriction would actually negate the effect needed for the desired outcome of improving erectile function.