Organophosphorus insecticide, monocrotophos, possesses the propensity to induce insulin resistance in rats on chronic exposure.
BACKGROUND
Our earlier studies had shown that monocrotophos (MCP), an organophosphorus insecticide (OPI), has the propensity to augment the secondary complications associated with type-1 diabetes. The present study investigates whether rats exposed for prolonged periods to monocrotophos would develop insulin resistance mediated by alteration in glucose homeostasis.


METHODS
Male rats were administered sublethal doses of monocrotophos daily for 180 days. Interim blood samples were collected to measure alteration in blood glucose and lipid profile. Rats were also subjected to glucose and insulin tolerance test and fasting blood glucose and insulin levels were measured to calculate insulin resistance by HOMA-IR method. After 180 days, the rats were also evaluated for pancreatic histology and activities of hepatic gluconeogenetic enzymes.


RESULTS
Monocrotophos elicited a gradual and sustained increase in blood glucose and insulin resistance in rats with concomitant glucose intolerance and reduced insulin sensitivity. MCP exposure was also associated with increase in weights of key white adipose pads, activities of gluconeogenesis enzymes and increase in pancreatic islet diameter, all of which led to hyperglycemia, hyperinsulinemia and dyslipidaemia.


CONCLUSIONS
Long-term exposure of rats to MCP resulted in glucose intolerance with hyperinsulinemia, a hallmark of insulin resistance. Our data suggest that chronic exposure to low doses of monocrotophos, might lead to development of insulin resistance by altering lipid profile and glucose homeostasis.
Food Protectants and Infestation Control Department, Council of Scientific and Industrial Research, Central Food Technological Research Institute, Mysore, India.
Raju
R
Nagaraju
Apurva Kumar Ramesh
AK
Joshi
Padmanabhan Sharda
PS
Rajini
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D018149:Glucose Intolerance / Q000139:chemically induced*; D006943:Hyperglycemia / Q000139:chemically induced*; D006946:Hyperinsulinism / Q000139:chemically induced*; D007306:Insecticides / Q000633:toxicity*; D007333:Insulin Resistance; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects*; D008055:Lipids / Q000032:analysis; D008297:Male; D008999:Monocrotophos / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D007306:Insecticides; D008055:Lipids; D008999:Monocrotophos
glucose homeostasis; hypertriglyceridemia; insulin resistance; monocrotophos; organophosphorus insecticides; 关键词：葡萄糖内稳态，高甘油三酯血症，胰岛素抵抗，久效磷，有机磷杀虫剂