EFFECT OF TEMPERATURE STRESS ON THYROID FUNCTION IN NORMAL ADULT RATS

Abstract

The thyroid gland is an important gland that secretes thyroid hormones such as T3 and T4 which control various life processes and metabolism in cells. Most of the available literature on thyroid gland function is limited to humans who sweat and less furred but knowledge on furred and non-sweating animals like rats which could serve as a good representative in this aspect is inadequate. Prior to the study, a confounding study was carried out on the effect of starvation in normal adult rats. A total of ten rats (Rattus norvegicus) were used, five were left to starve, and the rest were well fed on rat pencils bought from Nuvita feeds. The results revealed a significant (p=0.001) reduction in thyroid function in the starved rats. On this basis, therefore, throughout the study, all the rats were given the same treatment except in regard to feeding, oxygen concentration, light, genetic factor, and age except temperature treatment. The blood for testing the thyroid hormones was collected by cutting a small piece of the tip of the tail into an anticoagulant (heparin) bottle. The data collected were analyzed by the computer program XL--STAT 2008 version. One way-ANOVA was used to test for any significant increase or decrease in mean production ofT3, T4TSH, and FT4andpost Hoc, Tukey test was used to locate the increase or decrease. The findings showed that for both hypothermia and hyperthermia registered increased and decreased levels of T3 and T4 respectively. Unlike FT4levelwhere its level increased in hyperthermia and decreased in hypothermia, TSH, decreased in hypothermia and unaffected in the hyperthermia