Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 35 1 2013 04 04 The Effects of Acute or Chronic Immobilization Stress on Serum Levels of T3, T4 or TSH in Male Rats 6 11 EN Rahim Ahmadi Zahra Abbasi Vahid Asgary Journal Article 2012 06 26 2012 09 04 Backgrounds and Objectives: Different types of stress have different effects on the body's endocrine system. The main aim of this study was to determine the effect of acute and chronic immobilization stress on serum level of TSH, T3 and T4 in male rats. Materials and Methods: In this experimental study, male Wistar rats were randomly divided into controls, acutely immobilized (8h/day for immobilization 8 days) and chronically immobilized (2h/day immobilization for 21 days) groups, 10 in each group. After the periods of experiments, blood samples were collected using cardiac puncture method. Following serum collection, serum levels of TSH, T3 and T4 were measured by Electrochemiluminescense (ECL) method. The Data were statistically analyzed and compared between groups using One-Way ANOVA. Results: Results showed that serum TSH, T3 or T4 levels were significantly increased in rats during acute immobilization stress compared with control animals (P<0.001, P<0.001 and P<0.01, respectively) but there were not significantly different changed in thyroid hormones between animals with chronic immobilization and controls. Conclusion: Our findings show that acute immobilization stress enhances serum level of thyroid hormones.