We have done consecutive studies to investigate the effects of impaired lipid metabolism on the contractile and re-laxation response of cavernous smooth muscles and to elucidate its pathogenesis: 1) incidence of hyperlipidemia in im-potent patients; 2) erection response to intracavemous injection of papaverine in impotent patients with hyperlipidemia;3) relaxation responses of isolated cavemosal smooth muscles to endothelium-independent and endothelium-dependentvasodilators in impotent patients with hypercholesterolemia or hypertriglyceridemia; 4) involvement of superoxide radi-cal in the impaired endothelium-dependent relaxation of cavemous smooth muscle in hypercholesterolemic rabbits; S)effects of isolated lipoproteins and triglyceride, combined oxidized LDL plus triglyceride, and combined oxidized LDLplus HDL on contractile and relaxation response of rabbit cavemous smooth muscles; 6) involvement of e-NOS in theimpaired endothelium-dependent relaxation of cavemous smooth muscle in hypercholesterolem We have done consecutive studies to investigate the effects of impaired lipid metabolism on the contractile and re-laxation response of cavernous smooth muscles and to elucidate its pathogenesis: 1) incidence of hyperlipidemia in im-potent patients; 2) erection response to intracavemous injection of papaverine in impotent patients with hyperlipidemia; 3) relaxation responses of isolated cavemosal smooth muscles to endothelium-independent and endothelium-dependentvasodilators in impotent patients with hypercholesterolemia or hypertriglyceridemia; 4) involvement of superoxide radi-cal in the impaired endothelium-dependent relaxation of cavemous smooth muscle in hypercholesterolemic rabbits; S) effects of isolated lipoproteins and triglyceride, combined oxidized LDL plus triglyceride, and combined oxidized LDL plus HDL on contractile and relaxation response of rabbit cavemous smooth muscles; 6) involvement of e-NOS in theimpaired endothelium-dependent relaxation of cavemous smooth muscle in hypercholesterolem