Tissue Cholinesterase Inhibitory Action of Parathion

Rabbits were given parathion subcutaneously and the cholinesterase of tissues ere estimated manometrically. 1. Rabbits was given 100 mg/kg of parathion, and at the time of death in 45 minutes the cholinesterase activity of plasma fell to 15% of normal, erythrocyte 19%, spinal cord 22%, brain 25%, heart 45%, intestine 48%, kidney 49%, liver and muscle 51%, spleen 57%, lung 61% and stomach 87%. 2. Tissue cholinesterase activity of plasma of rabbits subcutaneouslly injected 5 mg/kg of parathion fell to 15% in 12 hours, lung 18%, 12 hs., erythrocyte 23%, 12 hs., kidney 23%, 48 hs., spleen 25%, 6 hs., stomach 33%, 6 hs., spinal cord 33%, 12hs., brain 41%, 6 hs., heart 45%, 6 hs., intestine 49%, 12 hs., liver 57%, 12 hs., and muscle 58%, 6 hs., 3. Discussion were made on these data.