Krishna, HRamachandran, A V2011-10-052011-10-052009-07Krishna H, Ramachandran AV. Combined effects of chlorpyrifos and lead on biochemical parameters after repeated dose 90-day dietary exposure in wistar rats. Journal of the Indian Society of Toxicology. 2009 Jul; 5(2): 11-18.http://imsear.searo.who.int/handle/123456789/134861The presence of organophosphorus pesticides and heavy metals as food contaminants along the food production line is a common finding. To investigate the interactive/combination effects of chlorpyrifos (CPF) and lead acetate (LA) on biochemical parameters, Wistar rats were exposed to both via dietary mode for a period of 90 days. The study was designed using two different dose levels of CPF and LA, and grouped into seven groups: control - 0 (Group 1), CPF - 1 (Group 2), LA - 50 (Group 3), CPF - 1 + LA - 50 (Group 4), CPF - 10 (group 5), LA 1000 (Group 6) and CPF - 10 + LA - 500 (Group 7) ppm. The haematology and clinical chemistry parameters were evaluated at the end of weeks 4 and 13 of exposure period, and after 4 weeks of recovery period. There were no significant changes in haematological parameters, except for a slight anaemic effect in leadtreated animals. Serum biochemistry revealed reductions in serum and RBC cholinesterase enzymes at the end of weeks 4 and 13 in groups 5 and 7. The 90-day exposure followed by a post-treatment free period of 28-days revealed higher inhibition of RBC cholinesterase enzyme in the recovery group of Chlorpyrifos-plus-Lead treated group, when compared with CPF-alone treated group. A similar trend was observed in serum glucose level of animals treated with a combination of CPF and lead after the treatment-free period of 28 days. The cholinesterase activity and serum glucose concentration observed in group 7 animals were not comparable to group 5 animals after 28 days of recovery period. The findings suggest long lasting and/or persistence of effects of a combination of chlorpyrifos and lead on glucose homeostasis and cholinesterase activity.enChlorpyrifosLeadSerum BiochemistryCholinesteraseArticle