Thyroxine is important for both collagen synthesis and matrix metabolism (Yen, 2001, Oliva et al.,2013). The thyroid hormones T4 and T3 are formed in a large prohormone molecule, thyroglobulin, the major component of the thyroid and more precisely of the colloid. Thyroid dysfunction may perturb the liver function and vice versa (N. Kumar, 2013). T3 stimulates synthesis and post­translational modification of type I collagen (Varga, et al., 2010), induces expression of alkaline phosphatase (Gouveia, et al., 2006) and regulates synthesis and secretion of the bone matrix proteins i. e. osteopoetin and osteocalcin (Gouveia et al., 2001, Varga et al., 2010). Recent study demonstrated the changes in liver collagen in Duttaphrynus melanostictus by daily administration of thyroid hormones (both T4& T3) at the dose of 0.5 µg/gm, for 7 days by the method of Newman & Logan (1950) as modified by Leach (1960). The salt soluble, acid soluble, insoluble, total collagen, % of salt solubility, % of acid solubility, salt soluble/ insoluble ratio, acid soluble/insoluble ratio of collagen were statistically found out at 0.05 P confidence level 

Keywords: Thyroid Hormone (T4& T3); Collagen; Duttaphrynus Melanostictus.