org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Time-Dependent Changes of Erectile Function in Diabetic Rats: Role of Systemic Endothelial D

Purpose: To understand the potential contribution of systemic endothelial dysfunction to diabetic erectile dysfunction, and the time course of erectile dysfunction in a streptozotocin (STZ)-induced diabetic rat model. Materials and Methods: Among 84, 12-week-old Sprague-Dawley rats, 48 rats received intraperitoneal STZ and were classified into six groups of diabetes by the period of observation (n=8). The remaining 36 rats were also grouped, similar to the diabetic groups, and served as normal controls. After 4, 6, 8, 10, 12, and 14 weeks of diabetes (serum glucose ＞250 mg%), all rats underwent cavernous nerve electrostimulation (3 V, 0.2 ms, 30 sec) with varying frequency (2.5∼20 Hz). At the end of the study, 8 ml of blood was taken to measure the plasma markers of endothelial function and glycosylated hemoglobin. Results: Compared to the control, significant reduction of erectile response was not observed until eight weeks after diabetes induction. The diabetic rats had elevation of all plasma markers except for l-selectin. However, the correlation analysis revealed that no systemic marker of endothelial dysfunction was associated with change in erectile function. Only the level of hemoglobin A1c (HbA1c) showed a modest but significant correlation with the peak intracavernosal pressure, corrected by mean arteria