Effect of acute and chronic simulated high altitude on male reproduction and testosterone level.

Forty, sexually mature, male rats were divided into two control and two treated groups. One of the treated groups was exposed five times to 6000 m of high altitude (acute exposure), and the other treated group was exposed 70 times (chronic exposure). Acute exposure had no pathological effect on the male reproductive tract or blood testosterone level; however, in animals that received chronic exposure, there was significant reduction in plasma testosterone level, 80% of spermatogenic tissue was highly vacuolated, nuclei of the interstitial tissue revealed pyknosis, and dilation of the blood vessels was noted throughout the testis.