Heat acclimation causes some alterations in serum enzymes activities in streptozotocin-diabetic rats

The present study investigated the effect of long-term heat acclimation and experimental diabetes on serum activity of transaminases (AST, ALT), ALP, LDH and elastase complex, as well as blood glucose and HbA1c level in Wistar rats. The heat acclimation model was established with the artificial heat chamber (35±1 °C and 30-40% humidity) for a period of 28 days, while the control groups were held on 20±2 °C. Experimental diabetes was induced by single streptozotocine (STZ) injection (55 mg/kg bodyweight) The changes caused by insulin treatment (2 IU/100 g body weight, 14 days, twice daily) in both thermal groups were also investigated.STZ-diabetes leads to significant increase in blood glucose and HbA1c level, AST, ALT and ALP activities in both thermal groups (normothermic and heat acclimated), decrease in LDH activity in normothermic animals and increase in heat-acclimated ones. Treatment with insulin restores the blood glucose, HbA1c and enzymes activities regardless of the previous thermal exposure.Prolonged acclimation of control animals to elevated ambient temperature resulted in significant decrease in blood glucose level, AST, ALT, ALP and LDH activities and non-significant changes in HbA1c. Compared to diabetic rats from room temperature, heat-acclimated diabetic ones have significantly higher blood glucose, AST, ALP and LDH activity, lower HbA1c concentration and no significant changes in ALT. Most of the changes observed in heat-acclimated insulin-treated diabetic rats did not significantly differ compared to those from room temperature.The overall two-way ANOVA analyses showed that diabetic state causes significant changes in the blood glucose, HbA1c, AST, ALT and ALP activity, while heat acclimation causes significant changes only in HbA1c level and AST activity. Both of the factors (diabetic state and heat acclimation) have significant common effects on AST, ALP and LDH activity.