[Kidney function and the glucocorticoid activity of the adrenal cortex during immersion]

The paper presents the study of renal and adrenal function in six normal men during and after 3-day water immersion used as weightlessness simulation. The renal excretion of fluid, basic electrolytes, creatinine and total 17-hydroxycorticosteroids (17-HOCS) for 24 hours and following a provocative water-load test (20 ml/kg) was measured. During the first post-immersion day diuresis increased by 77%, excretion of sodium by 42%, 17-HOCS by 43% and creatinine by 34% as compared to the pre-immersion level. Potassium excretion remained essentially unchanged. The circadian rhythm of excretion of the above substances was normal: at night the excretion decreased and in the morning increased noticeably. The study of renal function and adrenal activity was carried out 56 hours after the beginning of water immersion, using a provocative water-load test. Water excretory and osmoregulatory functions of kidneys, and glucocorticoid activity of adrenals remained normal. These data give evidence that during a 60 hour exposure to water immersion no functional hypocorticism develops.