[Status of water-electrolyte homeostasis and the systems of hormonal regulation during 237-day space flight].

On mission days 216-219 two crewmembers collected urine and recorded their food and water consumption during three days on end. The cosmonaut-physician withdrew blood samples from the vein and finger. In addition, he made venipuncture to himself and drew blood. Urine and blood samples were frozen and returned to the ground for analysis. In spite of individual variations of each cosmonaut, they all showed a trend for water and sodium retention which was provided by adequate hormonal rearrangement, i. e. increased production of ADH and aldosterone. No disorders in calcium and phosphorus metabolism were seen. Immediately postflight the cosmonauts displayed typical changes in fluid-electrolyte balance and renal function that suggested body dehydration and adjustment to Earth's gravity.