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Effects of space flight on endocrine system function in experimental animals
L Macho1, R Kvetnansky, S Nemeth
1Space Medicine Research Center, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
Environmental Medicine : Annual Report of the Research Institute of Environmental Medicine, Nagoya University
|December 1, 1996
Summary
Space flight alters rat hormones, affecting metabolism. Hormonal changes after long space missions are primarily due to re-entry stress, not prolonged microgravity exposure.
Area of Science:
- Space biology
- Endocrinology
- Physiology
Background:
- Space flight significantly impacts physiological systems.
- Understanding hormonal and metabolic adaptations is crucial for astronaut health.
Purpose of the Study:
- To investigate the effects of space flight on rat endocrine and metabolic systems.
- To compare space flight-induced changes with responses to terrestrial stress.
Main Methods:
- Rats were exposed to varying durations of space flight aboard COSMOS satellites.
- Plasma hormone levels (ACTH, growth hormone, TSH, prolactin, corticosterone, catecholamines, insulin, glucagon) and tissue enzyme activities were analyzed.
- Hypothalamic norepinephrine and catecholamine-synthesizing enzyme activity were measured.
- Results were compared to rats subjected to acute or repeated stress.
Main Results:
- Space flight induced pituitary morphological changes and altered plasma hormone levels, including decreased growth hormone and TSH, increased prolactin, and elevated corticosterone and catecholamines after longer flights.
- Metabolic enzyme activities in the liver and adipose tissue were affected.
- Hypothalamic norepinephrine decreased in specific regions, but overall synthesis activity remained unchanged.
- Plasma insulin and glucose increased, while glucagon remained stable.
- Long-duration space flight did not significantly activate the adrenocortical and sympathetic adrenomedullar systems.
Conclusions:
- Hormonal and metabolic alterations observed after space flight are likely influenced more by the acute stress of re-entry (gravitational stress) than by prolonged microgravity.
- Long space missions may not represent an intensive stress stimulus to the adrenocortical and sympathetic systems.