SEX ORGAN CHANGES AND BREEDING PERFORMANCE OF MALE RATS EXPOSED TO ALTITUDE: EFFECT OF EXERCISE AND PHYSICAL TRAINING

Summary. Exposure of male rats at rest to 21,500 ft simulated altitude 4 hr daily for 4 weeks induced testicular changes such as small to large vacuolated areas, pale fibrillar acellular areas and prematurely sloughed germinal cells in the seminiferous tubules. These changes, noted first following three exposures, increased in incidence for the next 25 days. Within 1 week, degenerate germinal cells were scattered among normal spermatozoa in the caput and caudal portions of the epididymis and after 4 weeks as many as one-fourth of the cells were abnormal. Similar changes were observed in the rats exercised at altitude. The weights of the seminal vesicles of rats at rest were not significantly reduced by altitude exposure, but exercise at altitude produced a 50 % reduction within 1 week. There were no significant weight or cellular changes in the testes or seminal vesicles in rats exercised at ground level. Exercise training for 3 weeks at ground level before exercise at altitude did not ameliorate the testicular changes, but significantly reduced the loss in weight of the seminal vesicles. Successful mating ensued in 2 to 4 weeks in 90 % of the resting rats exposed to altitude. The untrained rats exercised at altitude failed to mate, but 3 weeks of ground level physical training before exercise at altitude enabled 38 % of the rats to mate successfully