Effects of methimazole pretreatment on cerulein induced acute pancreatitis in rats

Abstract

Background: Many interrelationships exist between the thyroid gland and the gastrointestinal tract. Several past and recent studies have shown that the thyroid gland profoundly influences the structure and function of the exocrine pancreas in the rat. In the present study we investigated the effect of methimazole (METZ), an antithyroid drug, on cerulein induced acute pancreatitis (AP) in rats. Methods: Rats were divided into 3 groups (10-12 weeks age, 200-250 g weight, n: 10). Group B was made hypothyroid with methimazole 5 mg/kg daily for 10 days and the others were untreated euthyroid groups. After 10 days, acute pancreatitis was induced with four doses of 20 pg/kg body weight of cerulein administered s.c at hourly intervals in group A and B while the control group C was given 4 doses of 1 ml saline. Pancreas wet weight (mg), plasma amylase activity (IU/1) and pancreatic histology were used as endpoints to quantify the severity of the AP. Results: Plasma tri-iodothyronine (T3) (ng/d1) and thyroxine (T4) (µg/d1) levels were significantly reduced after METZ treatment for 10 days (p < 0.01). METZ pretreatment reduced significantly the cerulein induced increase in pancreatic weight (1205 ± 12 mg in METZ treated AP group versus 1617 ± 14 mg in AP group, p < 0.05) and the rise in amylase activity (7078 ± 816 IU/1 in METZ treated AP group versus 8611 ± 830 IU/1 in AP group p < 0.05). Conclusion: METZ reduces the severity of cerulein induced AP in rats. This effect might be through its antithyroid property.