Methyl parathion (20 mg · kg−1 intravenously and orally) and parathion (5 mg · kg−1 intravenously and 10 mg · kg−1 orally) were given to non-anesthetized dogs and the serum concentrations were followed in function of time. For both substances a low bioavailability after oral administration was found.
In other dogs radioactivity was followed in urine after oral and after intravenous administration of labeled methyl parathion or parathion. The results suggest a good gastro-intestinal absorption of the substances.
In anesthetized dogs which were given methyl parathion or parathion intravenously, high hepatic extraction ratios were found, suggesting that the low systemic availability after oral administration can be explained by an important hepatic first-pass extraction.
Binding of methyl parathion and parathion to dog serum, to human serum and to a solution of human albumin was determined with equilibrium dialysis. In both species a high binding (>90%) was found for both substances and there was no concentration-dependency in the concentration range used (0.2–30 μg · ml−1). In man and in dog the serum protein binding of parathion was about 5% higher than that of methyl parathion.
Organophosphates Dogs Methyl parathion Parathion Systemic availability First-pass Protein binding
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Baker SR, McGilliard AD, Dahm PA (1979) Uptake, clearance and metabolism of parathion by perfused whole pig livers. Pestic Biochem Physiol 11: 20–32CrossRefGoogle Scholar
Belpaire FM, Bogaert MG, Rosseneu M (1982) Binding of β-adrenoceptor blocking drugs to human serum albumin, to α1-acid glycoprotein and to human serum. Eur J Clin Pharamacol 22: 253–256CrossRefGoogle Scholar
Braeckman RA, Godefroot MG, Blondeel GM, Belpaire FM, Willems JL (1980) Kinetic analysis of the fate of methyl parathion in the dog. Arch Toxicol 43: 263–271CrossRefGoogle Scholar
Eto M (1974) Organophosphorus pesticides: organic and biological chemistry. CRC Press Inc, ClevelandGoogle Scholar
Fuhremann TW, Lichtenstein EP, Zahlten RN, Stratman FW, Schnoes HK (1974) Metabolism of [14C] parathion and [14C] paraoxon in isolated, perfused rat livers. Pestic Sci 5: 31–39CrossRefGoogle Scholar
Maliwal BP, Guthrie FE (1981) Interaction of insecticides with human serum albumin. Mol Pharmacol 20: 138–144PubMedGoogle Scholar
Miyamoto J, Sato Y, Kadota T, Fujinami A, Endo M (1963) Studies on the mode of action of organophosphorus compounds. Part I. metabolic fate of 32P labeled sumithion and methylparathion in guinea pig and white rat. Agric Biol Chem 27: 381–389Google Scholar
Mourik J, de Jong LPA (1978) Binding of the organophosphates parathion and paraoxon to bovine and human serum albumin. Arch Toxicol 41: 43–48CrossRefGoogle Scholar
Nakatsugawa T, Tolman NM, Dahm PA (1969) Degradation of parathion in the rat. Biochem Pharmacol 18: 1103–1114CrossRefGoogle Scholar
Neal RA (1972) A comparison of the in vitro metabolism of parathion in the lung and liver of the rabbit. Toxicol Appl Pharmacol 23: 123–130CrossRefGoogle Scholar
Okonek S (1976) Probable progress in the therapy of organophosphate poisoning. Extracorporeal hemodialysis and hemoperfusion. Arch Toxicol 35: 221–227CrossRefGoogle Scholar
Okonek S (1978) Elimination of parathion by hemoperfusion in severe E605 forte intoxication in vivo. Arch Pharmacol 302: R66Google Scholar
Okonek S, Boelcke G, Hollmann H (1976) Therapeutic properties of haemodialysis and blood exchange transfusion in organophosphate poisoning. Eur J Int Care Med 2: 13–18CrossRefGoogle Scholar
Pond S, Rosenberg J, Benowitz NL, Takki S (1979) Pharmacokinetics of haemoperfusion for drug overdose. Clin Pharmacokin 4: 329–354CrossRefGoogle Scholar
Poore RE, Neal RA (1972) Evidence for extrahepatic metabolism of parathion. Toxicol Appl Pharmacol 23: 759–768CrossRefGoogle Scholar
Skalsky HL, Guthrie FE (1977) Affinities of parathion, ddt, dieldrin and carbaryl for macromolecules in the blood of the rat and American cockroach and the competitive interaction of steroids. Pestic Biochem Physiol 7: 289–296CrossRefGoogle Scholar
Tilstone WJ, Winchester JF, Reavey PC (1979) Pharmacokinetic concepts. The use of pharmacokinetic principles in determining the effectiveness of removal of toxins from blood. Clin Pharmacokin 4: 23–37CrossRefGoogle Scholar
Wagner JG (1975) Fundamentals of clinical pharmacokinetics. Drug Intelligence Publications, Hamilton, IllinoisGoogle Scholar
Wilkinson GR, Shand DG (1975) A physiological approach to hepatic drug clearance. Clin Pharmacol Ther 18: 377–390CrossRefGoogle Scholar