Objectives: To investigate the relationship between penile erection induced by L-arginine in paraventricular nucleus (PVN) and androgen.
Methods: Twenty-four mature male rabbits were randomly divided into three groups which were castrate, castrate with testosterone propionate (T) replacement and pseudo-operation. One month later, the highest intracavernous pressure (ICP) and nitric oxide synthase (NOS) of each PVN tissue were measured after infusing L-arginine into the PVN.
Results: The mean ICPs of the highest values in castrate, castrate given T replacement and pseudo-operation groups were (22.640 +/- 4.747) mmHg, (38.146 +/- 4.907) mmHg and (39.991 +/- 3.068) mmHg, respectively. The mean value of NOS activity of each group were (0.807 +/- 0.188) U/mg.prot, (1.457 +/- 0.293) U/mg.prot and (1.528 +/- 0.204) U/mg.prot, respectively. The ICP and NOS activity in castrate were different statistically from T replacement and pseudo-operation group (both P < 0.01). T replacement group had no statistical difference from pseudo-operation group(P > 0.05).
Conclusions: Nitric oxide (NO) is one of the neurotransmitters in PVN particularly relevant for the control of penile erection. Penile erection induced by L-arginine in PVN depends on androgen.