Immunocytochemistry for manganese-superoxide dismutase (Mn-SOD) was studied in 12 normal adenohypophyses and 38 various pituitary lesions. The proportions of cells with granular immunoreactivity for Mn-SOD in normal adenohypophysis ranged from 9.8% to 29.6% (mean +/- SD; 18.4+/-6.2%). Some positive