<prompt> Thyroxine is synthesized from which amino acid-ArginineLysineMethionineTyrosine  <response>: Ans. is d i.e., TVrosine Thyroid hormones Important factso Thyroid hormones are T4 throxine and T3 Triiodothyroxineo Thyroid hormones are synthesised from amino acid tyrosine.o Their synthesis is regulated by TSH, a hormone secreted by anterior pituitary.o T3 is the active form and T4 is converted to T, in liver and kidney. Thus T4 mainly serves as transport form,o Circulating thyroid hormones are bound to thyroxine binding globulin fmain binding protein, throxine binding albumin and throxine binding prealbumin.o Thyroid hormone has two main function.i Morphogenesis: - Growth differentiation.ii Calorigensis : - It increases all metabolism producing energy. 