ROLE OF CORTICOSTERONE IN THE LOSS IN IMMUNE FUNCTION IN THE ZINC-DEFICIENT A-J MOUSE

Previous studies from this laboratory have shown that zinc deficiency causes a rapid atrophy of the thymus with subsequent loss of T-cell helper function in the young adult A/J mouse. The purpose of this investigation was to determine if zinc deficiency constituted a chronic stress on the mouse leading to the elevation of glucocorticoid levels which is known to destroy thymic lymphocytes. The results of these experiments indicate that zinc-deficient mice indeed have increased levels of plasma corticosterone (115μg/100 ml plasma) compared to mice fed zinc-adequate diets (40 μg/100 ml plasma). A significant reduction in T-cell helper function, which occurred 4 days after this rise in steroid concentration, suggests that corticosterone may contribute to the loss in immunity; however, about half of the total loss in T-cell helper function occurred prior to the increase in plasma corticosterone and was due to other factors associated with the lowered zinc levels.