Role of some vasoactive mediators in patients with erectile dysfunction: their relationship with angiotensin-converting enzyme and growth hormone

Abstract

The imbalance between vasoconstrictors and vasodilators may play an important role in the pathogenesis of erectile dysfunction (ED). A total of 36 patients with ED, organogenic [diabetic (n ¼ 12) and nondiabetic (n ¼ 12)] and psychogenic (n ¼ 12) etiology, and 12 healthy adult men as controls were included. The levels of endothelin-1 (ET-1), growth hormone (GH), angiotensinconverting enzyme activity (ACE), nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were determined in the flaccid penis cavernosal blood of patients and in cubital blood of patients and controls. In psychogenic ED, systemic ACE activity was elevated compared to controls (Po0.05). In diabetic and nondiabetic ED patients, systemic levels of ET-1 (Po0.0001 for both) and ACE activity (Po0.01 and o0.05) were higher while GH (Po0.0001 and o0.001), NO (Po0.0001 for both) and cGMP (Po0.01 for both) levels were lower compared to controls. In diabetic patients, systemic and cavernosal ET-1 levels (Po0.0001 for both) and cavernosal ACE activity levels (Po0.05) were significantly elevated while systemic and cavernosal NO (Po0.0001 for both) and GH (o0.001 and o0.05) levels were declined compared to psychogenic. In nondiabetic patients, systemic and cavernosal ET-1 levels (Po0.0001 for both) were significantly elevated while systemic and cavernosal NO (Po0.0001 for both) and systemic GH levels (Po0.05) were declined compared to psychogenic. Systemic NO was positively correlated with GH in psychogenic (r ¼ 0.616, Po0.05), diabetic (r ¼ 0.583, Po0.05) and nondiabetic (r ¼ 0.615, Po0.05) patients and correlated positively with cGMP (r ¼ 0.605, Po0.05) but negatively with ACE activities (r ¼ À0.585, Po0.05) in diabetic patients. In conclusion, plasma levels of ET-1, ACE activities are elevated and associated with reduction of GH, NO and cGMP levels in the systemic and cavernous blood of ED patients. This disturbance may indicate endothelial dysfunction that may hind at their significance in the pathophysiology of ED.

DOCA-salt treatment enhances responses to endothelin-1 in murine corpus cavernosumThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.

“…Accordingly, a high prevalence of erectile dysfunction (ED) is observed among hypertensive men (Lewis 2004;Muller and Mulhall 2006), and ET-1 is considered one of the best independent predictors for ED (Bocchio et al 2004). In addition, greater plasma levels of ET-1 were reported in the venous blood of patients with organic and psychogenic ED, but not in that of non-ED controls (Hamed et al 2003;El Melegy et al 2005). Furthermore, because ET-1 increases contractile responses to other vasoactive agents, one may speculate that increased contractions to EFS and phenylephrine are due to ET-1 effects.…”

Diagnostic value of nitric oxide, lipoprotein(a), and malondialdehyde levels in the peripheral venous and cavernous blood of diabetics with erectile dysfunction

“…25,26 In this study, we found a significant decrease of cavernosal and peripheral NO in diabetic patients, but not in patients with psychogenic ED, in agreement with others. 27 This finding could be due to the presence of advanced glycosylation end-products (AGEs), compounds that are formed as a result of non-enzymatic reaction between glucose and the amino groups of proteins. Advanced glycosylation end-products have been shown to quench NO and result in attenuation of NO-mediated relaxation of cavernosal smooth muscle.…”

Do motorcyclists have erectile dysfunction? A preliminary study

“…15 In ED patients, plasma levels of ET-1 are elevated, and are associated with reduction in growth hormone (GH), nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in systematic and cavernous blood. 16 The vibration to perineal lesion from the saddle in motorcycle riding may cause peripheral nervous damage and the elevation of plasma levels of ET-1, and reduction in GH, NO and cGMP in the cavernous blood. Therefore, the vibration from motorbike may cause ED, and the degree of vibration to perineal lesion might be associated with the severity of ED.…”