Histological examination of various tissues in rats with hypothyroidism induced by propylthiouracil or thyroidectomy

Despite the common use of propylthiouracil (PTU) to induce hypothyroidism, it causes degeneration of the thyroid gland, kidney and anterior pituitary tissue. The aim of our study was to determine changes in the liver, thyroid gland, kidney and anterior pituitary from male rats treated with PTU (10 m g/kg/day; for 2 weeks) and in thyroidectomy-induced hypothyroid male rats. Histological examination was performed by light microscopy. Total T3 and T4 levels were determined by radioimmunassay. In both PTU-treated and thyroid ectomized groups, plasma T3 and T4 levels were significantly lower than tho se in the control group. No abnormal changes were observed in the liver tis sue of the hypothyroid rats. There were significant decreases in the epith elial magnitude of degenerated follicular cells in the thyroid tissues of t he PTU-treated animals. Furthermore, these were seen in the lumen, which di d not contain colloid. There was mononuclear cell infiltration and haemorrh age in the kidney cortex and medulla in both the thyroidectomized and PTU g roups. The anterior pituitary in the thyroidectomized and PTU-treated rats showed a diffused hyperplasia. The tissue was locally haemorrhagic, and bas ophilic cells were frequently localized at the side of the haemorrhage. The se findings show that both PTU and thyroidectomy-induced hypothyroidism cau ses changes in the histology of the kidney, thyroid gland and anterior pitu itary. Med Sci Res 27:801-805 (C) 1999 Lippincott Williams & Wilkins.