PRINCIPAL INVESTIGATOR(S): Lawrence F. Dietlein, and Elliott S. Harris 



EXPERIMENT TITLE/NUMBER : Bioassay of Body Fluids - M005 



PROGRAM/MISSION : Gemini 7, 8, 9 



CLASSIFICATION : Human 



DISCIPLINE(S) : Hematology, Endocrinology 



OBJECTIVES : To determine the metabolic cost of manned spaceflight and to use 

 the results to indicate the physiological status of the crewmembers. 



PROTOCOL : Samples taken pre- and postflight of plasma/serum were assayed for 

 17-hydroxycorticosteroids, proteins, antidiuretic hormone, hydroxyproline, 

 electolytes, bilirubin, and uric acid. Pre-, post-, and inflight samples of 

 urine were assayed for volume, specific gravity, osmolality, pH, 

 17-hydroxycorticosteriods, electrolytes, catecholamines, nitrogenous 

 compounds, antidiuretic hormone and aldosterone. Plasma was taken immediately 

 after recovery, and at R+6, 24, and 72 hours. Urine was collected 

 continuously for 48 hours after flight. 



EQUIPMENT : Assay equipment and urine collection device. 



RESULTS : Electrophoretic patterns were normal. There was an increase in 

 17-hydroxycorticosteroids immediately after recovery, which returned to normal 

 within 6 hours. There was a drop in plasma uric acid, which may have been 

 caused by low purine intake. There was marked water retention immediately 

 postflight and retention of electolytes. This is consistent with the 

 hypothesis that atrial and thoracic stretch receptors are of physiological 

 importance in gravity change. 



CONCLUSIONS : Electrolyte and water retention observed immediately postflight 

 are consistent with the assumption that the Gauer-Henry atrial reflex was 

 responsive to a change from the weightless to the one-g environment. 

 Alterations in electrolyte and water distribution during the flight may have 

 been contributory. Immediately postflight, plasma 17-hydroxycorticosteroid 

 levels were elevated. Plasma uric acid was reduced. The cause of the 

 reduction is unknown, but is presumed to be dietary. 



PUBLICATIONS : 154, 155, 163, 249 



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