HYPERGRAVITY DOES NOT AFFECT TESTICULAR FUNCTION

Background: A previous study revealed that exposure of rats to microgr avity for 14 d on Cosmos 2044 reduced production of testosterone by >8 0%, although spermatogenesis remained essentially normal. Methods: To ascertain if testicular function was altered in hypergravity, 60-d-old rats were randomly assigned to 2 groups (10 per group) and subjected to 14 d of centrifugation to expose them to a total of 2G, or held at unit gravity in similar cages without centrifugation (control). Result s: After 14 d, body weight of 2G rats was essentially unchanged, where as that of control rats had increased; 310 vs. 377 g (p < 0.05). Teste s weight, production and secretion of testosterone, diameters of semin iferous tubules and their lumina, data from subjective evaluation of s permatogenesis, and counts of homogenization-resistant spermatids ail were similar for 2G and control rats. Conclusion: It was concluded tha t exposure of male rats to 2G for 14 d had no major effect on testicul ar function whereas, based on earlier studies, exposure to microgravit y (<10(-3) x gravity) for 11-14 d suppressed production of testosteron e by Leydig cells and reduced concentrations of anabolic steroids avai lable to peripheral tissues.