[Understanding disorders in the regulatory cycle of the thyroid. Significance for diagnosis and therapy]

In the regulating circle for the regulation of the functions of the thyroid gland interactions exist between hypothalamus, anterior lobe of the pituitary gland, thyroid gland and the concentrations of the thyroid hormone at the periphery. By means of the TRH-test the secretory work of the thyrotropic function of the hypophysis depending on the activity of the thyroid hormone can be judged. On the other hand, the T3-suppression test (radioiodine test before and after application of T3) allows a statement on the hypophyseal-thyroidal regulation. In contrast to the exclusive determination of the peripheral thyroid hormones by means of the TRH-test an etiologic differentiation of hypothyreoses and an essential improvement in the diagnosis and conduction of the therapy of thyroidal diseases and functional disturbances is made possible, as it is demonstrated at instances. By means of the T3-suppression test it is possible to establish, still under the treatment of a diffuse hyperthyreosis, whether the function of the thyroid gland is again regulated by the hypophysis or is still autonomous. Together with the result of the TRH-test decisions may be rendered on the end of the treatment or on the further course of the therapy.