IMPACT OF STRESS AND TRIIODOTHYRONINE ON PLASMA MAGNESIUM FRACTIONS

The differential regulation of free and bound plasma magnesium was stu died in healthy volunteers exposed to various forms of stress, and pat ients screened for thyroid disorder. Both ergometric (7 min) and psych ological (45 min) stress had no effect on free plasma magnesium, but i ncreased the bound fraction. Before combined physical and psychologica l stress (45 min aerobatics) there was no correlation between the plas ma fractions of magnesium; thereafter, there was a strong negative cor relation between increased free and decreased bound magnesium. Three d ays of training in ground combat increased significantly the plasma le vels of both magnesium fractions. Patients screened for thyroid disord er had a significant, positive correlation between both plasma fractio ns of magnesium, and a highly significant negative correlation between plasma T3 and the two magnesium fractions. No clear correlation betwe en plasma catecholamines and magnesium levels was seen under any of th e above conditions. Overall, the data show that the evaluation of the functions of circulating magnesium requires the specific measurement o f the free and bound fractions.