Hyperglycemic and stressogenic effects of monocrotophos in rats : Evidence for the involvement of acetylcholinesterase inhibition

• Published in: Experimental and toxicologic pathology : official journal of the Gesellschaft für Toxikologische Pathologie 2012, Vol.64 (1), p.115-120
• Main Authors: Joshi, Apurva Kumar R., Rajini, P.S.
• Format: Article
• Language: English
• Subjects: acetylcholine; Acetylcholinesterase; Acetylcholinesterase - metabolism; acute exposure; Adrenal Glands - drug effects; Adrenal Glands - enzymology; Animals; antagonists; Atropine; Atropine - therapeutic use; Atropine Derivatives - therapeutic use; Biological and medical sciences; Blood Glucose - analysis; brain; Brain - drug effects; Brain - enzymology; Cholinergic Antagonists - therapeutic use; Cholinesterase Inhibitors - toxicity; corticosterone; Corticosterone - blood; glycogen; Glycogen - metabolism; Hyperglycemia; Hyperglycemia - blood; Hyperglycemia - chemically induced; Hyperglycemia - enzymology; Hyperglycemia - prevention & control; Investigative techniques, diagnostic techniques (general aspects); lethal dose 50; liver; Liver - drug effects; Liver - enzymology; Male; Medical sciences; Methyl atropine; Monocrotophos; Monocrotophos - toxicity; nitrates; oral administration; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; pretreatment; Rats; Rats, Inbred Strains; Receptors, Cholinergic - metabolism; Stress, Psychological - blood; Stress, Psychological - chemically induced; Stress, Psychological - enzymology; Stress, Psychological - prevention & control; Stressogenic effect; tyrosine transaminase; Tyrosine Transaminase - metabolism
• ISSN: 0940-2993; 1618-1433
• DOI: 10.1016/j.etp.2010.07.003

The purpose of this study was to investigate the involvement of acetylcholinesterase (AChE) inhibition in hyperglycemic and stressogenic effects of monocrotophos in rats. Oral administration of monocrotophos (1.8 mg/kg b.w., 1/10 LD 50) caused reversible hyperglycemia in rats with peak increase occurring at 2 h following administration. The hyperglycemic outcome at 2 h was accompanied by significant inhibition of acetylcholinesterase (AChE) activity in brain (84%), adrenal (68%) and liver (53%) and stressogenic effects as revealed by marked increase in plasma corticosterone (102%) and liver tyrosine aminotransferase (TAT) (104%) activity. At 4 h following administration, there was normalization of hyperglycemia and hypercorticosteronemia, marginal attenuation of liver TAT activity and marked increase in liver glycogen content, without spontaneous reactivation of AChE activity in the organs studied. Interestingly, pre-treatment of rats with acetylcholine (ACh) receptor antagonists—atropine sulfate and methyl atropine nitrate offered significant protection against hyperglycemia, hypercorticosteronemia and increased liver TAT activity induced by monocrotophos. Our results clearly demonstrate the involvement of AChE inhibition in hyperglycemia and stressogenic effects of monocrotophos in rats following acute exposure. Protection offered by both, general and peripheral ACh antagonists provide further evidence for the involvement of peripheral AChE inhibition in the monocrotophos-induced effects.