Histological and Physiological Changes in the Kidneys of Female Albino Rats Treated with Levothyroxine

Abstract

Background: Levothyroxine is a common medication used to treat hypothyroidism. Administering it in high doses for extended periods can affect many organs in the body.

Objective: The objective of the study was to evaluate the physiological and histological effects of levothyroxine at different doses on kidney tissue in female albino rats.

Methodology: This experimental study was conducted at the University of Karbala, College of Education for Pure Sciences, Department of Biology, from October 2025 to April 2026. The effect of levothyroxine was investigated at three concentrations. The study was performed on 20 female albino rats, and the drug's effect on the physiological and histological aspects of the kidneys was examined.

Results: The renal cortex had obvious pathological alterations, including structural and vascular anomalies as well as inflammatory infiltration, according to histological analysis. The control group's physiological results revealed normal values for urea (32.80 ± 3.17) and creatinine (0.28 ± 0.03). At 50 μg/kg, these values rose to 1.08 ± 0.08 for creatinine and 54.40 ± 2.22 for urea; at 100 μg/kg, they rose to 1.84 ± 0.18 and 82.80 ± 2.00, respectively. The highest values of creatinine (2.44 ± 0.12) and urea (104.40 ± 5.41) were recorded at the 150 microgram/kg dose, suggesting a progressive decline in kidney function with increasing dosage.

Conclusion: Levothyroxine leads to negative effects on the kidney, represented by increased levels of urea and creatinine and the occurrence of pathological tissue changes.

Bangladesh Journal of Infectious Diseases, June 2026;13(1): 144-152