1 Plant Archives Vol. 21, Supplement 1, 2021 pp. 1728-1733 e-ISSN:2581-6063 (online), ISSN:0972-5210 Plant Archives Journal homepage: http://www.plantarchives.org doi link : https://doi.org/10.51470/PLANTARCHIVES.2021.v21.S1.274 HISTOLOGICAL AND PHYSIOLOGICAL STUDY OF THYROID DYSFUNCTIONS ON OVARY IN FEMALE RATS (RATTUS RATTUS) Marwah Najeh Hammood and Ekhlas Abid Hamza College of Veterinary Medicine, University of Al-Qasim Green, Iraq. Email : aljubourimarwa86@gmail.com ABSTRACT The present study was approved to investigate the effects of thyroid dysfunctions were induced in female albino rats on thyroid gland and ovary, in the case of hyperthyroidism we used Levothyroxine (LVX), and in case of hypothyroidism we used Carbimazole (CBZ), Then measure hormonal levels of thyroid and examine the histological changes of thyroid gland and ovary. Uses for this study forty albino female rats aged twenty weeks old and weighed between 200-300g were separated randomly into four groups: Group I was administration orally 100 μg/kg b.w. of LVX for three months. Group II was administration orally 5mg/kg/ b.w. of CBZ for three months while Group III was orally administration 1ml of normal saline only (0.09%) as a control group for three months. Group IV has orally administration a mix of 50 μg/kilogram for the bodyweight of LVX for six weeks+2.5 mg/kilogram for the bodyweight of CBZ for six weeks. Finally, all the animals were scarified and then blood collection, thyroid, and ovary samples were taken. Physiological study contain thyroid hormones levels measured by using the Enzyme-Linked Immunosorbent Assay (ELISA) kit, we showed significantly (p < 0.01) increase levels of Triiodothyronine (T3), Tetraiodothyronine (T4), in contrast decrease levels of thyroid-stimulating hormone (TSH) levels in Group I treated with LVX while group observed significantly (p < 0.01) decrease in levels of (T4), (T3), while TSH level increase. The fourth group, showed a slight increase in the levels of thyroid hormones. The results of histological study revealed that, Group I an increase in the colloid resorption with vacuolation of the nuclei of epithelial cells that lining the follicles of the thyroid; formation of corpus luteum in ovarian tissue with the presence of one secondary follicle in Group II. Group III showed a decrease in the colloid resorption with formation of multiple ovarian cysts and hemorrhagic cysts while the histological changes in Group IV showed active thyroid follicles with the presence of resorption vacuoles and congestion blood vessels and formation of many primordial follicles and primary antral follicles of ovarian tissue. Keywords : TSH, Levothyroxine, Carbamazole, Ovary. Introduction The thyroid gland is the very important organs of the endocrine glands and its weight ranged (15-20) gram. It has red in clour and soft in consistency, and lie between the C5- T1 vertebrae of columna vertebral is, below the larynx and front of the trachea. It is consisting of two lobes (lobus sinister and lobusdexter) and there are between it. The thyroid has external and internal folium is folded by a fibrosis capsule (Abalovich et al., 2007). The thyroid gland produces Triiodothyronine (T3) and Thyroxin (T4) that have great importance in body functioning. Thyroid hormones have many target tissues in the body with a wide physiological role in the control of growth, development, and metabolic activities of organs. Certain plasma levels of these hormones are required for normal gonadal functions. Inadequate thyroid hormone supply causes abnormal folliculogenesis and anovulation in female rats and mice (Sato and Jiang, 2001) Hypothyroidism is a mean decrease of the thyroxin hormone concentration, wherever it causes a decrease in the heart rate and weakens the heartbeat the heart becomes less efficient leading to breathing short during the exercise due to the narrowing of the arteries results in of the blood pressure. If the hypothyroidism is not treated, is results in peripheral neuropathy. The peripheral neuropathy included several changes in the nerves that transfer the stimulus between the central nervous system and the body. In some cases, the thyroid can produce too much of its hormones, which is called hyperthyroidism or overactive thyroid. Clinical signs are include feeling irritable and nervous, low attention, the problem in concentrating, body warm, increased heartbeat, sleep disorder, diarrhea, and losing weight. Sometimes, there is thyroid gland swelling called a nodule. Sometimes, these nodules haven’t an impact on the gland function but sometimes results in the secretion of the thyroid hormones at a large amount or sometimes. These nodules may be benign or cancer (Keleş and Keleş, 2008). Thyroid hormones are included Thyroxine and Triiodothyronine that have great importance in the growth, the differentiation, and metabolism of all organs such as the function of the endometrium and ovaries ((Krassas, Poppe and Glinoer, 2010). The function of the thyroid is essential to general health and reproduction (Muderris et al., 2011), so, the reproduction of the females is decreased in hypothyroidism and hyperthyroidism ((Kang et al., 2013)).