A 65-year-old man with type 2 diabetes mellitus visits the office because his sexual performance has declined over the last six months. His libido, muscle strength, and energy level are normal, according to the patient, but his erections are inconsistent, weak, and of insufficient duration for sexual activity. Although he has a history of hypertension, he has no history of coronary artery disease and no suspicious chest pain. The results of bilateral ankle brachial index testing are within normal limits. The patient is given sildenafil, which significantly improves his sexual performance. The intracellular signaling of this drug is most similar to that of which of the following substances?

Question

Quizplus · Accepted Answer

Eductional Objective: Atrial natriuretic peptide, brain natriuretic peptide, and nitric oxide activate guanylyl cyclase and increase conversion of guanosine 5'-triphosphate to cyclic guanosine 3',5'-monophosphate (cGMP). Phosphodiesterase inhibitors (eg, sildenafil) decrease the degradation of cGMP. Elevated intracellular cGMP levels lead to relaxation of vascular smooth muscle and vasodilation.

A 65-Year-Old Man with Type 2 Diabetes Mellitus Visits the Office