Effect of +Gz and +Gx acceleration on peripheral venous ADH levels in humans.

Abstract
The effect of +2 Gz and +2 Gx acceleration for 30 min. on the peripheral venous ADH [antidiuretic hormone] levels in human subjects was studied on the Unites States Air Force-SAM [School of Aerospace Medicine] human centrifuge. A mean rise in the blood ADH level of 2.97 [mu]U/ml (P<0.05) was found during the +GZ runs, and this rise could be inhibited by having the subjects wear an anti-G suit inflated to 60 mm Hg. A mean decrease in the blood ADH level of 0.89 [mu]U/ml (P<0.05) was found during Gx accleration. These results support the assumptions that changes in urine volume during +GZ and +Gx acceleration are probably a result of changes in ADH secretion.