Abstract

Objective: In thyroid hormone level disorders such as hypothyroidism and hyperthyroidism in developmental period, experimental studies have shown that structural and functional changes in the brain. These changes are known to cause neurological disorders and impairments in cognitive processes, such as learning and memory, in which the hippocampus plays an important role. For this purpose, it is aimed to investigate spatial learning performance between hyperthyroidized male and female rats. Materials and Methods: Male and female rats were administered with L-thyroxine intraperitoneally at a dose of 0.2 mg/kg for 21 days to induce hyperthyroidism. Morris water maze (MWM) was used to assess learning and memory performance. Results: When repeated ANOVA tests were performed, the gender factor significantly affected the mean distance to the platform (p <0.001). In the following days and trials, the average distance of female rats to the platform is greater than male rats. This data suggest that female rats were swum longer distance to the platform and found the platform later. This effect of the gender factor was not affected by hyperthyroidism. In terms of memory performance, hyperthyroid group rats showed a significant decrease compared to the control group (p=0,023). It was also observed that gender difference increased this decrease in hyperthyroid state (p=0,020). It was observed that the ratio in the target quadrant of female hyperthyroid rats was lesser. Conclusion: As a result, spatial learning and memory performance in hyperthyroid rats varies according to sex.

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