Changes of insulin in plasma and receptor for insulin in various tissues after the exposure of rats to space flights and hypokinesia.
The explanation of the mechanism of the response to gravity changes is of great importance for the determination of the capacity of human subjects to adapt to the load of gravitational stress.  Therefore several studies were performed to investigate the activity of endocrine system, since the hormones are involved in the regulation of physiological functions and metabolic processes.  However the studies of endocrine system activity during altered gravity conditions, especially during the weightlessness are influenced by the several interventions in biomedical observations due to operational program of astronauts, wide variability in individual response and tolerance, use of extensive countermeasures, differences in the type of space missions and in the studies after landing also a hypergravity effect at landing and variability in postflight readaptation process.  The significant changes of plasma insulin and glucose levels were observed in astronauts during space flights and in the first days of recovery period.  In the first inflight period plasma insulin levels were increased, unchanged or decreased however after 4-5 weeks of exposure to weightlessness a decrease of insulin plasma levels were noted.  After space flights an increase of plasma insulin levels were demonstrated in experimental animals and in human subjects.  Since plasma insulin level is considered as most important factor involved in the regulation for insulin receptors in target tissues, an investigation of insulin receptors in various tissues was performed in rats exposed to space flight or to hypokinesia (model used for simulation of some effects of microgravity).
Macho
L
L
Institute of Experimental Endocrinology, SAS, Bratislava, Slovakia.
Fickova
M
M
Svabova
E
E
Zorad
S
S
Serova
L
L
Popova
I
I
D000273:Adipose Tissue / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D006614:Hindlimb; D007103:Immobilization / Q000502:physiology*; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011972:Receptor, Insulin / Q000032:analysis* / Q000378:metabolism; D012149:Restraint, Physical; D013026:Space Flight; D014893:Weightlessness; D018474:Weightlessness Simulation
D007328:Insulin; D011972:Receptor, Insulin