[State of the pituitary-adrenal system of cosmonauts after orbital flights of different duration].

In order to assess the hypophyseal-adrenal system and glucocorticoid activity, excretion of total 17-hydroxycorticosteroids (17-HOCS) was measured before and at R + 1 day after a standard water load (20 ml/kg). Twenty-six cosmonauts were examined after flights of 2--140 days. Although the cosmonauts spent different time in weightlessness, the content and rate of glucocorticoid excretion in the urine during postflight water loads was 1.5--2 times higher than during preflight loads. This increased excretion of 17-HOCS was associated with their decreased reabsorption and/or increased glomerular secretion. The latter may be a manifestation of extrarenal action of ACTH due to its hyperproduction immediately postflight.