Relationship between dietary protein level and enzymatic changes in acute poisoning of rats with chlorfenvinphos

The acute oral toxicity (LD50) of chlorfenvinphos (Chl) showed no significant difference between Wistar rats (males and females) aged 42 days kept for 30 days on 4.5% or 26%-protein diet, but a twofold difference appeared after 60 days on these diets (LD50 was lower in low-protein rats) showing that a longer period of protein deficiency more increases the susceptibility of rats to the lethal action of Chl. During acute poisoning produced by intragastric administration of single convulsive dose of Chl (30 mg/kg body weight) to rats kept for 30 days on low-protein or optimal-protein diet, changes were observed in the activity of some enzymes in the serum and brain. Protein deficient diet increased the Chl-produced inhibition of acetylcholinesterase (AChE) activity in the brain; the augmented activity of aspartate aminotransferase (AspAT) and alanine aminotransferase (AlaAT) and glucosephosphate isomerase (PHI) appeared only in the serum of low-protein rats--these changes were more marked in females. Other enzymatic alterations caused by Chl were similar independently of the diets and also more evident in females; for comparison the rats received also standard Murigran diet. Activity of the brain aromatic amino acids aminotransferases (AAA) showed a decreasing trend in Chl-poisoned rats, while in the liver the activity of these enzymes rose, but chiefly in the rats receiving previously the diet with 26% of protein or standard diet. In the rats surviving the acute Chl poisoning, with the evidently seen convulsions, the activity of nearly all enzymes was normal after 14 days.