Effects of acute cold exposure (10 degrees C for 60 min) on the concentrations of adrenocorticotropin (ACTH) and zinc in plasma were investigated in seven healthy male students. There were no significant changes in total zinc, albumin-bound zinc, and alpha 2-macroglobulin-bound zinc concentrations throughout the experimental period. On the other hand, ACTH concentration increased markedly during cold exposure. In addition, a statistically significant inverse relationship existed between the changes in ACTH and albumin-bound zinc values during the experiment. These results suggest that acute cold exposure produces elevated plasma ACTH levels, with resulting zinc redistribution in the human body.