Influence of synthetic corticosteroids on plasma zinc and copper levels in humans.

The effects of varying doses of a short-acting (methylprednisolone) and a long-acting (dexamethasone) synthetic glucocorticoid on extent and duration of alterations in plasma zinc and copper concentrations in normal humans are documented. Early after intravenous administration of either steroid, increases in plasma zinc and copper levels were observed. By 12 hours, plasma zinc concentrations had decreased below control levels and the extent and duration of the depression depended on the dosage of the steroid administered. No significant decrease was noted beyond 48 hours. The plasma copper levels did not decrease until after zinc levels began returning toward normal, reaching a peak depression at 48 hours and, at high doses of steroids, persisting until completion of the study at 96 hours. This difference in the time sequence suggests that different mechanism control plasma concentrations of the two metals. The serum zinc levels may depend on ACTH-adrenal interactions, while the slower response of the serum copper levels may depend on changes in the rate of synthesis of the serum copper-binding protein, ceruloplasmin.