Correlation of homocysteine in plasma with NOS and endogenous CO in the penile corpus cavernosum of type 2 diabetic rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the correlation of homocysteine (Hcy) in plasma with nitric oxide synthetase (NOS) and endogenous carbon monoxide (CO) in the penile corpus cavernosum of type 2 diabetic rats.</p><p><b>METHODS</b>This study included 40 male Wistar rats, 10 as controls (Group A) and the other 30 as diabetes mellitus (DM) models. Four weeks after the model establishment, the model rats were divided into a DM group (Group B, n = 10), an insulin treated group (Group C, n = 10), and a folic acid and vitamin B12 treated group (Group D, n = 10). All the rats were injected with apomorphine and observed for penile erection at 8 and 12 weeks, and the levels of total plasma Hcy (tHcy), NOS and CO in the penile corpus cavernosum were measured at 12 weeks.</p><p><b>RESULTS</b>Compared with Group A, the level of tHcy was significantly increased, while NOS and CO activities in the penile cavernous tis-sue and erectile function remarkably decreased in Group B (P < 0.01). The incidence rate of high Hcy was 55% in the DM rats. In comparison, the level of tHcy was obviously decreased, and the NOS activity and erectile function markedly increased in Groups C and D (P < 0.01). The Hcy level showed a significant negative correlation with NOS activity (rA = -0.89, rB = -0.76, rc = -0.91, rD = -0.91) and CO content (TA = -0.82, r, = -0.77, rc = -0.93, rD = -0.81).</p><p><b>CONCLUSION</b>High plasma Hcy can decrease NOS and CO activities in the penile corpus cavernosum, and consequently induce erectile dysfunction in DM rats, while insulin, folic acid and vitamin B12 can improve their penile erectile function by increasing NOS and CO activities.</p>

Nitric oxide synthetase and carbon monoxide decrease in the penile corpus cavernous of hyper homocysteine rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To detect the levels of nitric oxide synthetase (NOS) and carbon monoxide (CO) in the penile corpus cavernous of adult male Wistar rats with high homocysteine (Hhcy) and to explore the relationship of NOS and CO levels with erectile dysfunction.</p><p><b>METHODS</b>Twenty Wistar rats were equally and randomly divided into a control and an Hhcy group and fed on normal diet and normal diet with 3.0% methionine respectively. Four weeks later, the levels of NOS and CO in the penile corpus cavernous were detected by ultraviolet spectrophotometry and that of serum homocysteine by the cycle enzyme method.</p><p><b>RESULTS</b>Compared with the control group, the levels of NOS and CO in the penile corpus cavernous were significantly lower in the Hhcy group, (6.45 +/- 1.12) nmol/(g x min) vs (10.77 +/- 0.60) nmol/(g x min) and (10.60 +/- 0.92) micromol/L vs (13.36 +/- 0.44) micromol/L, while that of homocysteine was significantly higher, (22.32 +/- 1.65) micromol/L) vs (4.90 +/- 1.73) micromol/L.</p><p><b>CONCLUSION</b>Four-week diet with methionine can cause Hhcy and significantly decreased levels of NOS and CO in the penile corpus cavernous in Wistar rats. Hhcy is an independent risk factor of erectile dysfunction.</p>