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Physiological Systems Experiment (PSE-1)
Principal Investigator
Research Area:
Muscle physiology
Species Studied
Scientific Name: Rattus norvegicus Species: Rat Strain: Wistar


The objective of this experiment was to test the hypothesis that a growth-hormone (GH) deficiency occurs during space flight and that this deficiency contributes to the bone loss and decreased tissue function observed following microgravity exposure. It was expected that replacement with recombinant GH inflight, in combination with adequate nutrition and exercise, would halt the process of bone and tissue degeneration. As the first commercially sponsored life science payload, the experiment was to investigate whether biological changes caused by microgravity were similar enough to Earth-based medical conditions to facilitate pharmacological evaluation of potential new therapies. Other objectives included evaluation of muscle and immune function, which are known to be affected/regulated by GH.

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Cronin, M. et al.: Delivery of Recombinant Human Growth Hormone to Rats During Exposure to Microgravity on NASA Space Shuttle Discovery. Physiologist, supl., vol. 35, no. 1, 1992, pp. S51-S52.

NASA: Recent Flight Results: STS-41. Commercial Space Developments, NASA Office of Commercial Programs, vol. 1, no. 3, 1990, p. 4.

Nash, P. and A. Mastro: Variable Lymphocyte Responses in Rats after Spaceflight. Experimental Cell Research, vol. 202, 1992, pp. 125-131.

Tidball, J.G. and D.M. Quan: Reduction in Myotendinous Junction Surface Area of Rats Subjected to 4-Day Spaceflight. Journal of Applied Physiology, vol. 73, no. 1, 1992, pp. 59-64.

Immune system
Bone and bones

Data Information
Data Availability
Archive is complete. All data sets are on the Web site.
Data Sets + View data.

Area, Cortical section, femur, bone, rat, microscopy
Area, Cortical section, humerus, bone, rat, microscopy
Area, cross section, Fiber, soleus, muscle, rat, Immunochemistry, microscopy
Area, surface, Femur, bone, rat, Microscopy
Area, surface, Humerus, bone, rat, Microscopy
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
STS-41 10/06/1990 10/10/1990 4 days

Additional Information
Other Key People
Managing NASA Center
Ames Research Center (ARC)
Responsible NASA Representative
Ames Research Center LSDA Level 3
Project Manager: Martha Del Alto
Institutional Support
National Aeronautics and Space Administration (NASA)
Protocol / Approach
Protein treated
Asynchronous control