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Influence of Altered Mass Loading on Testosterone Levels and Testicular MassEffects of altered load on testosterone levels and testicular mass in mammals are not well defined. Two separate studies (loading;centrifuged; +2G(sub z) and unloading;hindlimb suspension;HLS) were conducted to provide a better understanding of the effects of mass loading on testosterone levels and testicular mass. Daily urine samples were collected, and testicular mass measured at the end of the study. +2G(sub z): Sprague-Dawley rats (230-250 g) were centrifuged for 12 days at +2G(sub z): 8 centrifuged (EC) and 8 off centrifuge controls (OCC). EC had lower body mass, however relative testicular mass was greater. EC exhibited an increase in excreted testosterone levels between days 2 (T2) and 6 (T6), and returned to baseline at T9. HLS: To assess the effects of unloading Sprague-Dawley rats (125-150 g) were studied for 12 days: 10 suspended (Exp) and 10 ambulatory (Ctl). Exp had lower body mass during the study, with reduced absolute and relative testicular mass. Exp demonstrated lower excreted testosterone levels from T5-T12. Conclusions: Loading appears to stimulate anabolism, as opposed to unloading, as indicated by greater relative testicular mass and excreted testosterone levels. Reported changes in muscle mass during loading and unloading coincide with similar changes in excreted testosterone levels.
Document ID
Document Type
Conference Paper
Wang, Tommy J.
(NASA Ames Research Center Moffett Field, CA United States)
Ortiz, R. M.
(NASA Ames Research Center Moffett Field, CA United States)
Wade, C. E.
(NASA Ames Research Center Moffett Field, CA United States)
Hargens, Alan R.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Aerospace Medicine
Meeting Information
Meeting: FASEB Conference
Location: New Orleans, LA
Country: United States
Start Date: April 6, 1997
End Date: April 9, 1997
Sponsors: Federation of American Societies for Experimental Biology
Funding Number(s)
PROJECT: RTOP 947-30-60
PROJECT: RTOP 106-20-01-02
Distribution Limits
Work of the US Gov. Public Use Permitted.

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