Hepatic injury and disturbed amino acid metabolism in mice following prolonged exposure to organophosphorus pesticides

1 Chronic occupational exposure to organophosphorus and carbamate-type pest icides significantly inhibits acetylcholinesterase activity and causes morb idity, This study on mice was designed to evaluate their amino profile and to identify signs of hepatic dysfunction following their chronic exposure t o mixtures of organophosphorus pesticides. 2 Laboratory mice were exposed to a formulated mixture of the six organopho sphorus pesticides (Dimethoate, Chlorpyrifos, Profenofos, Pirimiphos methyl , Triazophos and Dimethoate) most commonly used in agriculture in this regi on of the Middle East, Doses (10% of LD50 of the mixture) were given once a week by gavage in corn oil for 7 weeks; the control group was given only c orn oil, At the end of the exposure period, mice were culled and blood samp les were collected to determine erythrocyte acetylcholinesterase activity, biochemical markers of liver function and concentrations of serum amino aci ds, 3 Erythrocyte acetylcholinesterase activity and total serum proteins decrea sed significantly in the exposed group. Serum concentrations of alanine ami notransferase and aspartate aminotransferase, alanine, glutamic acid, glyci ne, isoleucine, leucine, methionine, ornithine, proline, serine, threonine and valine were significantly increased in the exposed mice, while serum le vels of cystine were decreased significantly. There were also non-significa nt increases in serum alkaline phosphatase, gama-glutamyl transpeptidase an d some of the other amino acids. 4 Chronic exposure to mixtures of organophosphorus pesticides is associated with decreased acetylcholinesterase activity, hepatic dysfunction and dist urbance of amino acids profile. Biochemical indices of hepatocellular injur y and disturbed amino acid metabolism may be of value as markers of chronic exposure to such pesticides.