Effects of microgravity or simulated launch on testicular function in rats
| Autor: | R. P. Amann, D. R. Deaver, B. R. Zirkin, G. S. Grills, W. J. Sapp, D. N. Veeramachaneni, J. W. Clemens, S. D. Banerjee, J. Folmer, C. M. Gruppi, al. et |
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| Rok vydání: | 1992 |
| Předmět: |
Genetic Markers
Male medicine.medical_specialty Physiology medicine.drug_class Mice Inbred Strains Biology Testicle Chorionic Gonadotropin Mice Physiology (medical) Internal medicine Testis medicine Animals Spermatogenesis Heat-Shock Proteins Testosterone Leydig cell Weightlessness Vivarium Leydig Cells Rats Inbred Strains Organ Size Space Flight Androgen Sertoli cell Rats medicine.anatomical_structure Endocrinology Gene Expression Regulation Luteinizing hormone |
| Zdroj: | Journal of Applied Physiology. 73:S174-S185 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | Testes from flight rats on COSMOS 2044 and simulated-launch, vivarium, or caudal-elevation control rats (5/group) were analyzed by subjective and quantitative methods. On the basis of observations of fixed tissue, it was evident that some rats had testicular abnormalities unassociated with treatment and probably existing when they were assigned randomly to the four treatment groups. Considering rats without preexisting abnormalities, diameter of seminiferous tubules and numbers of germ cells per tubule cross section were lower (P less than 0.05) in flight than in simulated-launch or vivarium rats. However, ratios of germ cells to each other or to Sertoli cells and number of homogenization-resistant spermatids did not differ from values for simulated-launch or vivarium controls. Expression of testis-specific gene products was not greatly altered by flight. Furthermore, there was no evidence for production of stress-inducible transcripts of the hsp70 or hsp90 genes. Concentration of receptors for rat luteinizing hormone in testicular tissue and surface density of smooth endoplasmic reticulum in Leydig cells were similar in flight and simulated-launch rats. However, concentrations of testosterone in testicular tissue or peripheral blood plasma were reduced (P less than 0.05) in flight rats to less than 20% of values for simulated-launch or vivarium controls. Thus spermatogenesis was essentially normal in flight rats, but production of testosterone was severely depressed. Exposure to microgravity for greater than 2 wk might result in additional changes. Sequelae of reduced androgen production associated with microgravity on turnover of muscle and bone should be considered. |
| Databáze: | OpenAIRE |
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