[Changes of endocrine hormones during -6 degrees head down bed rest in human].

Objective: To investigate changes of endocrine hormones during 7 d head down bed rest (HDBR).

Method: Six healthy male volunteers served as the subjects and experienced 7 d -6 degrees HDBR. Urine was collected from 6:00-22:00 and from 22:00-6:00. Serum was collected 48 h before HDBR, 48 h and 120 h during HDBR. Then the endocrine indices in urine and serum were determined.

Result: 1) The levels of serum CORT and ALD increased at 48 h during HDBR, while serum T3, T4, TP, UN decreased but they all recovered to normal at 120 h during HDBR. 2) The level of urine CORT, ALD and NE reached its peak in 24-48 h, and then gradually decreased to normal level.

Conclusion: The endocrine indices in serum and urine changed in the early period but returned to normal level gradually with the proceeding of HDBR.