INTRODUCTION The extensive use of organophosphate pesticides has long been pointed out to exert detrimental effects on the living organisms 1 . Organophosphate pesticides competitively inhibit pseudocholinesterase and acetylcholinesterase (ChE), preventing hydrolysis and inactivation of acetylcholine. Acetylcholine accumulates at nerve junctions, causing malfunction of the sympathetic, parasympathetic and peripheral nervous systems. Clinical signs of cholinergic excess develop. Numerous compli- cations are seen in organophosphate pesticides intoxication cases 2-5 . There are many kinds of organophosphorus pesticides, however phosalone was reported to lead to pancreatitis and liver damage amongst. Phosalone is one of the most widely used organophosphate pesticides in agriculture. Some of the toxic effects of phosalone are due to the inhibition of acetylcholines- terase, an enzyme needed for proper nervous system function. It can overstimulate the nervous system causing nausea, dizziness, confusion and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death 6 . Phosalone Toxicity on Liver and Pancreas: Role of Vitamins E and C HILMI DEMIRIN 1,* , OSMAN GÖKALP 2 , ERTUGRUL KAYA 3 , BORA BÜYÜKVANLI 4 , GÖKHAN CESUR 4 , AYBARS ÖZKAN 5 and MURAT KAYA 5 1 Department of Biochemistry, School of Medicine, University of Duzce, 81620 Duzce, Turkey 2 Department of Pharmacology, School of Medicine, University of Dicle, 21280 Diyarbakir, Turkey 3 Department of Pharmacology, School of Medicine, University of Duzce, 81620 Duzce, Turkey 4 Department of Physiology, School of Medicine, University of Suleyman Demirel, Isparta, Turkey 5 Department of Pediatric Surgery, School of Medicine, University of Duzce, 81620 Duzce, Turkey *Corresponding author: E-mail: hilmidemirin@hotmail.com (Received: 21 January 2012; Accepted: 15 November 2012) AJC-12408 Phosalone (6-chloro-3-[diethoxyphosphinothioylsulfanylmethyl]-1,3-benzoxazol-2-one) is one of the most commonly used organophosphorus pesticides in the pest control of crops. Subchronic phosalone exposure was evaluated for its effects on the serum activities of some enzymes concerning hepatic and pancreatic damage including aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamyltransferase (GGT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), cholinesterase (ChE); and finally protective effects of combination of vitamins E and C in 24 wistar-albino rats. Experimental groups were as follows: control group (n = 8); a group treated with 120 mg/kg body weight phosalone (P group, n = 8); and a group treated with 120 mg/kg body weight phosalone + vitamin E + vitamin C (P+V group, n = 8). The P and P+V groups were treated orally with phosalone on 5 days a week for 4 weeks. The serum activities of the above mentioned enzymes were analyzed. In the samples, phosalone significantly increased the activities of ALT, LDH and decreased ChE (p < 0.05). However no significant change was detected for the remainder enzymes (p > 0.05). In the P+V group, ALT and LDH activities were significantly increased and ChE decreased (p < 0.05). It is concluded that subchronic phosalone causes rat liver damage to an extent, which is somewhat reflected on the liver enzymes. Furthermore, a combination of vitamins E and C can reduce the toxic effects of phosalone on liver tissue of rats. Key Words: Phosalone, Toxicity, Liver, Pancreas, Enzymes. Phosalone has been reported to cause acute pancreatitis in humans 7 . Based on histochemical examination of the acinar tissue, pancreatic tissue-fixed butyryl cholinesterase is the target enzyme of organophosphate toxicity was suggested. It has been reported that inhibition of pancreatic butyryl choli- nesterase leads to cholinergic hyperstimulation of the acinar cell, resulting in acute pancreatitis 8 . Pancreatitis incidence rate was reported 12 % in the literature 3 . According to the 1996 data, it is estimated that 363,000 people have experienced organophosphate-induced acute pancreatitis yearly 9 . However, unconsciousness of the patient and complexity of the mani- festation make it harder to diagnose this condition 2 . Some authors have reported 10-13 that organophosphate pesticides cause severe hepatic damage, as well, which is marked by certain hepatic enzymes. Exposure of hepatocytes accelerates cellular damage as well as the loss of cellular ATP 14 . Phosalone, as well as some other organophosphate insec- ticides, was claimed to exert deleterious effects on various tissues besides acetylcholinesterase inhibition via increasing reactive oxygen species and these effects were reported to Asian Journal of Chemistry; Vol. 25, No. 5 (2013), 2589-2592