ASGSB 1998 Annual Meeting Abstracts

[73]
TESTOSTERONE AND AN ANABOLIC STEROID ALLEVIATES WEIGHTLESSNESS INDUCED MUSCULO-SKELETAL LOSSES.   S.M. Wimalawansa, D.J. Simmons,¹ M.Quast,² K. Westlund,² J. Wei,² and S.J. Wimalawansa. Departments of Internal Medicine, Anatomy and Neurosciences², Orthopedic Surgery¹, University of Texas Medical Branch, Galveston, Texas, 77555.

Simulation of mcrogravity isknown to cause rapid bone and muscle loss. Because, serum testosterone level become negligible in the tail-suspended (TS) rat, we hypothesized that the replacement of testosterone during TS could prevent those musculo-skeletal losses.

10-week old male Wistar rats were randomly allocated to received single injection of a placebo (control), or 16 mg/kg testosterone, or the anabolic steroid nandrolone decanoate (ND) (n=10/group) and were tail-suspended for 12 days. An additional 10 rats were injected with the vehicle and kept as ground controls. Bone and muscle changes were quantitated using nuclear magnetic resonance imaging, and bone mineral density (BMD) with DXA. The muscle mass of the ground control rats was significantly greater than the placebo-treated TS rats (56.5 ± 1.8, vs, 42.9 ± 3.0 density units, p<0.01). Testosterone and ND prevented the reduction of muscle loss (51.5 ± 2.2, 51.6 ± 1.2; 63% improvement; p<0.05). The BMD of the placebo-treated TS rats were significantly lower than that of ground control rats (0.416± 0.011 vs. 0.354 ± 0.014, p<0.05), and testosterone and ND prevented this bone loss (0.404 ± 0.013 vs. 0.409 ± 0.011, respectively).

These data suggest that both testosterone and ND therapy can prevent the musculo-skeletal losses associated with exposure to simulated weightlessness.

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