L-arginine is the substrate for the enzyme nitric oxide synthase ( NOS ), which is
responsible for the production of nitric oxide (NO), an endogenous messenger
molecule involved in many metabolic processes. The purpose of this work was to
evaluate the effect of L -arginine on male sex organs under diabetic conditions. In
this study three groups of adult male rats were used, the first as control, the second
was alloxan – induced diabetic rats under control by insulin and the third was like the
second but was treated with L-arginine for four weeks. At the end of the experiment ,
the rats were killed . The serum level of glucose, testosterone, body weight, serum
cholesterol, penile nitric oxide synthase (NOS) activity, arginase activity in (seminal
vesicle and prostate gland), lag time and erection time were estimated. The glucose
level was significantly increased in both second and third groups due to effect of
alloxan and was less significantly increased inthe third group due to the effect of L–
arginine. There was also significant decreasein serum testosterone in the second and
the third groups in relation to the control group, with no significant change between
the second and third groups. There was a significant increase in the level of serum
cholesterol and in the lag time in both groups 2 and 3, with significant decrease in the
third group in relation to the second group. The other remaining parameters showed
a significant decrease in both second and third groups in relation to the control
group with significant improvement in the third group when compared with the
second group due to the effect of giving L-arginine . We suggest that these findings
due to the beneficial effect of L- arginine on the sexual functions of the male sex
organs that were affected by diabetes.