Changes in glucose, insulin, and growth hormone levels associated with bedrest.

Changes in plasma glucose, insulin, and growth hormone (HGH) resulting from exposure to 56 d of bedrest were determined in five healthy young male subjects. Blood samples were collected by repeated venous puncture at 4-h intervals for 48-h periods before bedrest, at 10, 20, 30, 42 and 54 d after confinement to bed and at 10 and 20 d after bedrest. Changes in the daily levels of these factors for each subject were expressed as the mean of the six samples per 24-h period.

Mineral and nitrogen balance study observations: the second manned Skylab mission.

A metabolic study of the effects of space flight on various chemical elements, particularly those with special revelance to the musculoskeletal system, was carried out on the three astronauts of the SL-3 mission for 21 d preflight, during the 60 d flight phase, and for 17 d postflight. The study required of the cooperating crewmen quite constant dietary intake, continuous 24-hour urine collections and total fecal collections. Urinary calcium was significantly increased during flight in all three crewmen with man-to-man variation in pattern and amount; the degree of calcium loss was, in general, similar to that in the prior study of the 28-d Skylab flight (SL-2).

Metabolic and endocrine studies: the second manned Skylab mission.

This study conducted on the crewmembers of Skylab 3 was designed to evaluate the endocrinological adaption resulting from extend exposure to a space flight environment by identifying changes in hormonal and associated fluid and electrolyte parameters. The three men served as their own controls and were on a constant dietary intake. Complete metabolic collections were performed beginning 21 d before the flight, continuing throughout the flight, for 18 d postflight.

Mineral and nitrogen metabolic studies on Skylab flights and comparison with effects of earth long-term recumbency.

A metabolic study of the effects of space flight on various chemical elements, particularly those with special relevance to the musculo-skeletal system, was carried out on the nine astronauts who participated in the three Skylab flights of 28, 59 and 84 days in 1973-1974. The study required of the cooperating crewmen constant dietary intake, continuous 24-hour urine collections and total fecal collections for 21-31 days before each flight, throughout each flight and for 17-18 days post-flight. Increases in urinary calcium and negative calcium balances during space flight were generally similar to those found in previous immobilization and bedrest studies.

Acomparative study of two methods of urine preservation.

In preparation for the conduct of biochemical experiments in the Skylab Orbital Workshop a study was performed on the stability of various chemical constituents in urine in 2 different techniques for preservation and storage. Urine samples were either vacuum dried or frozen and maintained in storage at minus 20 degrees for periods of up to 10 weeks. The urinary constituents studied included aldosterone, antidiuretic hormone, epinephrine, norepinephrine, urea, nitrogen, creatine, hydroxyproline, 17-hydroxycorticosteroids, calcium, sodium potassium, chloride, magnesium and phosphate.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: appendix III. evaluation of viscera and other tissues.

Histopathological findings in the lungs, livers, bone marrows, small intestines, gonads, kidneys, and other tissues of the four pocket mice (Perognathus longimembris) that survived the Apollo XVII flight were evaluated in the light of their immediate environment and as targest of HZE cosmic ray particles. Results of this study failed to disclose changes that could be ascribed to the HZE particle radiation. Decreased numbers of erythropoietic cells in the bone marrow of the flight mice were probably related to the increased oxygen pressure.

Mineral and nitrogen balance study: results of metabolic observations on Skylab II 28-day orbital mission.

Prediction that the various stresses of flight, particularly weightlessness, would bring about significant derangements in the metabolism of the musculoskeletal system has been based on various observations of long-term immobilized or inactive bed rest. The only attempt at controlled measurement of metabolic changes in space prior to Skylab, a study during the 14-day Gemini VII flight, revealed rather modest losses of important elements. The three astronauts of Skylab II consumed a planned day-by-day, quite constant, dietary intake of major metabolic elements in mixed foods and beverages and provided virtually complete collections of excreta for 31 days preflight, during the 28 days inflight, and for 17 days postflight.

Endocrine responses in long-duration manned space flight.

The bioassay of body fluids experiment is designed to evaluate the biochemical adaptation resulting from extended exposure to space flight environment by identifying changes in hormonal and associated fluid and electrolyte parameters reflected in the blood and urine of the participating crewmen. The combined stresses of space flight include weightlessness, acceleration, confinement, restraint, long-term maintenance of high levels of performance, and possible desynchronosis. Endocrine measurements to assess the physiological cost of these stresses have been considered from two aspects.

Calcium and phosphorus change of the Apollo 17 crew members.

In association with the 12.6-day lunar flight of Apollo 17, calcium and phosphorus intake and excretion were determined for the crew members before and during the mission. The study showed increased urinary and fecal phosphorus and increased fecal calcium during weightlessness.

Plasma thyroxine changes of the Apollo Crewman.

Blood drawn from Apollo crew member; to the mission, at recovery, and postmission was used to examine the effect Apollo mission activities have on tyroid hormone levels. At recovery, statistically significant increases in thyroxine and the free thyroxine index were found. Serum cholesterol and triglycerides were decreased.