Tadpole Ii PDF Download

Thyroid hormones role in development was first suggested in the 18th century when a relationship between goiter and cretinism was found by F.E. Fodere. But it was Rudolf Virchow work in the late 19th century with thyroidectomized animals that clearly demonstrated that goiter led to cretinism. This opened the door to the understanding of TH action on vertebrate development. However given the relative ease by which cretinism could be treated simply by eating animal thyroid gland or iodine supplementation, research into the action of TH on vertebrate development has been lagging. This was further enhanced by the complex biology of TH where, after production in the gland, entry, activation and binding of the TH to cognate receptors in target cells is highly regulated. Nonetheless, new scientific advances and technologies are now providing tools to dissect the developmental role of TH on vertebrate development, both embryonic and post-natal. The post-natal role of TH in vertebrate development is long known from anuran studies but less evidences exist from other vertebrates. Recently, new evidences show that TH constitute key developmental signal in embryonic development of vertebrates, especially in neural development, from humans to fish. This new evidences are corroborating long-standing observations that infants from mothers with impaired TH physiology presented changes in mental and cognitive indexes. Nonetheless, given that TH constitute integrative physiological signals in vertebrates a new scenario is emerging whereas TH seem to be important in the development and maturation of most organ systems in vertebrates during their different life transitions