Water deprivation and food restriction on toxicity of parathion and paraoxon.

Three groups of rats were injected intraperitoneally with either parathion or paraoxon: (1) rats deprived of water for 48 hr, (2) rats allowed water ad lib but restricted in food intake to equal that consumed by water-deprived rats, and (3) controls. Following injection of parathion all groups showed a progressive decrease in enzymatic hydrolysis of acetylcholine over a 2-hr period. The decrease was significantly greater in food-restricted rats. Injection with paraoxon resulted in an immediate decrease in red cell cholinesterase activity, which remained low for 1 hr, but recovered thereafter. The esterase activity of both deprived groups was significantly lower than that of controls. These experiments suggest that persons subject to nutritional deficiency and water deficit may be abnormally susceptible to the effects of anticholinesterase pesticides.