<prompt> TSH on surface receptor uses second messenger ascAMPcGMPCa2IP3  <response>: Thyroid-stimulating hormone TSH is a hormone secreted by the pituitary gland that controls the release of T3 and T4 by the thyroid gland.The thyrotropin receptor or TSH receptor is a receptor and associated protein that responds to thyroid-stimulating hormonealso known as thyrotropin and stimulates the production of thyroxine T4 and triiodothyronine T3. The TSH receptor is a member of the G protein-coupled receptor superfamily of integral membrane proteins and is coupled to the Gs protein.Upon binding circulating thyrotropin, a G-protein signal cascade activates adenylyl cyclase and intercellular levels of cAMP rise .cAMP activate all functional aspects of the thyroid cell, including iodine pumping; thyroglobulin synthesis, iodination, endocytosis and proteolysis; thyroid peroxidase activity; and hormone release.Ref: Ganong;s review of medical physiology;24th edition; page no-302 