Melatonin Receptor (Mt1 and Mt2) Proteins Expression in Thyroid Gland and Level of Thyroxin (T4), Thyrotropin (Tsh) Hormone During Progression of Age in Male Swiss Albino Mice

Abstract

Advancement of age is related with a progressive declining in most of the physiological activities. The activity of thyroid gland is also disturbed with increment of age in the organism. Melatonin regulates most of the physiological activities through its membrane bound MT1 and MT2 receptors in mammals. Melatonin receptors were localized on thyroid gland but their abundance on thyroid gland along with progression of age was unknown. In present study we investigated the age related changes in serum T4, TSH level and the abundance of melatonin receptor (MT1 and MT2) proteins in thyroid gland following the immunohistochemical study and western blot analysis. Decreased serum T4 level was noted in aged mice whereas serum TSH level was remained unchanged. Both MT1 and MT2 melatonin receptor proteins abundance was decreased with advancement of age in mice. Our present study may suggest that aging modulates the responsiveness of thyroid gland to melatonin through modulation of melatonin receptor (MT1 and MT2) proteins on thyroid gland. Further, this modulation may be responsible for contribution in the declining of physiological status of the thyroid in the organism.