Parathion-methyl effect on the activity of hydrolytic enzymes after single physical exercise in rats

Rats were subjected to physical exercise in the form of a single race in a treadmill. Unexercised animals and those immediately or 1 h after the exercise were given oil or oily solution of parathion-methyl in a dose of 10 mg/kg by stomach gauge. At 1 h after pesticide administration the activity of cholinesterase (ChE) was determined in the serum, of paraoxonase--in the serum and liver, and that of beta-glucuronidase (beta-gluc)--in the serum, liver and intestine. Single physical exercise increased ChE activity in the serum, inhibited paraoxonase activity in the serum and liver; on the other hand, it did not affect significantly beta-gluc activity in the serum, but inhibited that enzyme in a transient manner in the liver and activated it in the intestine. In acute poisoning with parathion-methyl it was observed that ChE and paraoxonase activities were inhibited, while beta-gluc activity was enhanced in the serum. Single physical exercise either diminished or had no effect on enzymatic changes observed in acute poisoning with parathion-methyl.