Template-Type: ReDIF-Article 1.0 Author-Name: Prashanjit Laskar Author-Workplace-Name: Department of Zoology, Tripura University, Suryamaninagar, Tripura, India Author-Name: Shiv Shankar Singh Author-Workplace-Name: Department of Zoology, Tripura University, Suryamaninagar, Tripura, India Title: Concomitant and Pre-emptive Melatonin Administration Improves Thyroid Hormones Level and Spleen T-cells Proliferation in Propyl-thiouracil (PTU) Induced Hypothyroid Condition in Swiss Albino Mice Abstract: Hypothyroidic development is associated with the disruption of thyroid secretions along with noticeable deterioration of body defense mechanism. The epiphyseal hormone melatonin was detected as an ameliorator of many unsuitable situations of mammalian physiology. In such context the current study was planned out to observe the role of melatonin in thyroid secretions and proliferation of immune cells in experimentally induced hypothyroid condition in mice. The levels of thyroid hormones were checked by ELISA kits. Proliferation of immune cells were assayed through analyzing the spleen T-cells proliferation. The level of thyroid hormones and spleen T-cells proliferation rate were significantly deteriorated in hypothyroid condition. Both concominant and pre-emptive melatonin administration significantly recovered the level of thyroid hormones in hypothyroid condition. Whereas, elevation of spleen T-cells proliferation was recorded only in pre-emptive treatment of melatonin in hypothyroid condition. This performed investigation delineated the concomitant and pre-emptive therapeutic potentiality of melatonin in the improvisation of disturbed thyroid activity and immune responses in hypothyroid condition. Keywords: Melatonin, Hypothyroid, Thyroid hormones, Splenocytic proliferation Journal: Inventum Biologicum: An International Journal of Biological Research Pages: 6-10 Volume: 5 Issue: 3 Year: 2025 File-URL: https://journals.worldbiologica.com/ib/article/view/185 File-Format: text/html File-URL: https://journals.worldbiologica.com/ib/article/view/185/353 File-Format: Application/pdf Handle: RePEc:adg:ibijbr:v:5:y:2025:i:3:p:6-10