Effect of hypothyroidism on the testes in mature rats and treatment with levothyroxine and zinc

This study was performed to investigate the effect of propylthiouracil (PTU ) on rat testis, and to compare the results of the different treatment regi mens of levothyroxine and zinc. Twenty sexually mature Wistar albino rats w ere subjected to PTU for 14 days intraperitoneally to make them hypothyroid ic. The effect of PTU on testicular function was assessed histopathological ly after unilateral orchiectomy on day 15, and treatment was evaluated by m easuring serum thyroid-stimulating hormone (TSH), T3, T4, and zinc levels o n days 0, 7, and 15. The rats were then divided into five groups which were given levothyroxine and/or zinc treatment for 15 days. Orchiectomies were repeated on day 30, and specimens were evaluated histopathologically. Altho ugh serum T3, T4 and zinc levels decreased, serum TSH levels increased in P TU-treated rats, and the difference to the control group was statistically significant (P < 0.001). Maturation arrest of spermatogenesis, a reduced nu mber of Sertoli and Leydig cells, a decreased tubular diameter, interstitia l oedema, and thickening of basal membrane were observed in hypothyroidic t esticles. After treatment, testicular histology and spermatogenesis gradual ly recovered in all groups with hypothyroidism, but maximum improvement was achieved in the levothyroxine + zinc sulphate replacement group, indicatin g a possible role of zinc in testicular function.