Objective  To study the relationship of hypoxia simulating high altitude and sexual function of rats.   Methods  Totally 60 adult male SD rats (3 months old) were randomly divided into control and hypoxia groups for 2

4 and 6 weeks (n=15 in each group). The rats of hypoxia groups were put into a hypobaric chamber simulating 4500-meter high altitude for 2

4 and 6 weeks (23 h/d)

and their sexual behaviors (times and latency of mount

intromission and ejaculation)

apomorphine-induced penile erections

content of testosterone in the serum

and nitric oxide synthase (NOS) and Masson staining in penis were examined.   Results  Compared with the control group

the sexual behaviors and the number of apomorphine-induced penile erections of hypoxia groups for 2

4 and 6 weeks were significantly inhibited (P0.05)

and testosterone in the serum and NOS activity in the penis of the experimental groups were reduced (P0.05). Masson staining showed that smooth fibers were decreased while collagen fibers were increased. Those changes were correlated with time elapse (P0.05).   Conclusion  The sexual function of rats is gradually restricted with increased time of hypoxia exposure in high altitude circumstance.