Erectile failure in cynomolgus monkeys with atherosclerosis of the arteries supplying the penis

We evaluated by direction observation the sexual behavior of normal and atherosclerotic adult male cynomolgus monkeys (Macaca fascicularis) toward sexually receptive female cynomolgus monkeys. Marked deficits in erectile and ejaculatory function were found in the atherosclerotic monkeys. These animals were normal in other aspects of social and sexual behavior and had normal concentrations of circulating testosterone. At necropsy, histopathologic evaluation of the urogenital vasculature revealed atherosclerotic lumen obstruction of internal iliac, internal pudendal and penile arteries which apparently resulted in diminished in vivo capacity of these vessels to accommodate the large increases in blood flow required for the production of an erection. These findings provide further evidence for the existence of an association between atherosclerotic obstruction of the internal iliac, pudendal and penile arteries and the occurrence of erectile failure, and suggest the usefulness of the nonhuman primate as an animal model for clinical studies of atherosclerotic sexual dysfunction of man.