Apoptosis was followed in L5178Y lymphoma cell-bearing mice at different times after intraperitoneal injections of adriamycin (ADM). Apoptosis was determined morphologically and confirmed by DNA laddering on electrophoresis. Apoptosis was observed 36h after injection of 5mg/kg ADM (apoptotic cell index 64.2+/-5.6 vs. 1.5+/-2.1 from the untreated group) and confirmed by DNA electrophoresis. However, when the animals were pretreated with (+)-alpha-tocopherol acid succinate or superoxide dismutase before ADM administration apoptotic index significantly diminished (P