title: Hypergravity does not affect testicular function.
abstract: BACKGROUND
  A previous study revealed that exposure of rats to microgravity for 14 d on Cosmos 2044 reduced production of testosterone by > 80%, 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).
  
  
  RESULTS
  After 14 d, body weight of 2G rats was essentially unchanged, whereas that of control rats had increased; 310 vs. 377 g (p < 0.05). Testes weight, production and secretion of testosterone, diameters of seminiferous tubules and their lumina, data from subjective evaluation of spermatogenesis, and counts of homogenization-resistant spermatids all were similar for 2G and control rats.
  
  
  CONCLUSIONS
  It was concluded that exposure of male rats to 2G for 14 d had no major effect on testicular function whereas, based on earlier studies, exposure to microgravity (< 10(-3) x gravity) for 11-14 d suppressed production of testosterone by Leydig cells and reduced concentrations of anabolic steroids available to peripheral tissues.
authors.affiliation: Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins 80523, USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Veeramachaneni
authors.forename: D R
authors.initials: DR
authors.lastname: Deaver
authors.forename: R P
authors.initials: RP
authors.lastname: Amann
mesh_terms: D000818:Animals; D001835:Body Weight; D002498:Centrifugation / Q000009:adverse effects*; D018471:Hypergravity / Q000009:adverse effects*; D018472:Hypogravity / Q000009:adverse effects; D008297:Male; D009929:Organ Size; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012671:Seminiferous Tubules / Q000502:physiology / Q000648:ultrastructure; D013076:Sperm Count; D013091:Spermatogenesis / Q000502:physiology; D013737:Testis / Q000502:physiology* / Q000648:ultrastructure*; D013739:Testosterone / Q000097:blood / Q000378:metabolism; D013997:Time Factors
chemical_list: D013739:Testosterone