The peripheral effect of thyroid hormones

: Human metabolism depends on not only extracellular processes: TSH production and secretion and thyroid gland secretion of hormones but also intracellular processes: active membrane transport of hormone, specific receptor-binding of hormone and the post-receptor effect. All these processes participate in maintaining a normal thyroid state in normal conditions and in disease. Only serum hormone concentration is routinely examined and it is therefore important to observe patients in which a discrepancy between the clinical condition and serum hormone measurements is evident as treatment with antithyroid drugs or hormone substitution may be irrational.