RED-BLOOD-CELL ANTIOXIDANT ENZYMES IN RATS AFTER A SINGLE CIRCADIAN-MODULATED DELIVERY OF 5-FLUOROURACIL

We have studied the status of the red blood cell antioxidant enzymes g lutathione reductase (GR), glutathione peroxidase (GP), glutathione tr ansferase (GT), superoxide dismutase (SOD) and catalase (CAT) in rats following a circadian-modulated delivery of the chemotherapeutic agent 5-fluorouracil (5-FU). There was a circadian variation in both GR and GT, with maximum activity during the dark/activity span. 5-FU signifi cantly enhanced GR activity (P < 0.01) and lowered GT activity (P < 0. 01); these effects were not dose-related and showed no circadian varia bility. GP, SOD and CAT activities were not subject to circadian varia tion. 5-FU had no effect on GP or SOD activity, but elicited a signifi cant decline (P < 0.05 and 0.01, respectively) in CBT activity in the dark/activity span. Med Sci Res 26:571-572 (C) 1998 Lippincott William s & Wilkins.