ABSTRACT
OBJECTIVE: The aim of the present study was to compare the effects of iopanoic acid (IOP) or a saturated solution of potassium iodide (SSKI) administration to patients with toxic diffuse goiters (TDG). DESIGN: Patients with TDG are treated with thionamides and high doses of iodine preoperatively. In this study, two types of preoperative drug regimens were used: propylthiouracil or methimazole plus SSKI for 10-15 days (n=8) or IOP for 7 days (n=6). METHODS: Serum thyroid hormones (total and free thyroxine (T(4)), total tri-iodothyronine (T(3)) and reverse T(3) (rT(3)), were evaluated after 7 days of either SSKI or IOP treatment, and after 10-15 days of SSKI administration. During thyroidectomy, samples of thyroid gland were obtained to evaluate thyroperoxidase and thyroid H(2)O(2)-generating activities. RESULTS: Serum total T(3) was significantly decreased after 7 days of either treatment, and serum rT(3) was significantly increased in IOP-treated patients. Serum total and free T(4) were unaffected by 7 days of IOP treatment, but decreased after 7 days of SSKI treatment, although significantly diminished levels were only reached after a further 3-8 days of SSKI administration. During both drug regimens, serum TSH remained low (SSKI: 0.159+/-0.122; IOP: 0.400+/-0.109 microU/ml). Thyroperoxidase activity was significantly lower in thyroid samples from patients treated with SSKI for 10-15 days than in the thyroid glands from IOP-treated patients. However, thyroid H(2)O(2) generation was inhibited in samples from patients treated with either IOP or SSKI. CONCLUSIONS: We show herein that IOP treatment can be effective in the management of hyperthyroidism and that this drug inhibits thyroid NADPH oxidase activity, just as previously described for SSKI, probably due to its iodine content.
Subject(s)
Goiter/drug therapy , Hydrogen Peroxide/metabolism , Iodide Peroxidase/metabolism , Iopanoic Acid/therapeutic use , Potassium Iodide/therapeutic use , Thyroid Gland/drug effects , Adolescent , Adult , Calcium/pharmacology , Enzyme Inhibitors/therapeutic use , Female , Goiter/surgery , Humans , Male , NADP/pharmacology , NADPH Oxidases/antagonists & inhibitors , NADPH Oxidases/metabolism , Potassium Iodide/administration & dosage , Thyroid Gland/enzymology , Thyroid Gland/metabolism , Thyroidectomy , Thyroxine/blood , Triiodothyronine/blood , Triiodothyronine, Reverse/bloodABSTRACT
A acromeglaia é uma sindrome causada pela hipersecçäo do hormônio de crescimento (GH). No entanto, alguns pacientes podem apresentar níveis séricos limítrofes, ou mesmo dentro da normalidade, dificultando o diagnóstico. Relatamos uma caso de acromegalia cuja investigaçäo diagnóstica inicial evidenciou níveis séricos basais de GH dentro dos limites da normalidade e tomografia computadorizada (TC) de sela túrcica normal. A confirmaçäo da doença só foi estabelecida através de testes dinâmicos que avaliam a regulaçäo do GH (dosagem de GH durante o teste oral de tolerância à glicose e após TRH) e confirmada pela ressonância nuclear magnética (RNM) de sela túrcica que evidenciou imagem sujestiva de microadenoma. A paciente foi submetida à cirurgia hipofisária pela via de acesso oronaso esfeinodal e a área tumoral encaminhada para estudo himunohistoquímico, corroborando o diagnóstico de acromegalia. A avaliaçäo dinâmica do pós operatório evidenciou regulaçäo normal do GH. discutimos os critérios diagnósticos da acromegalia, com ênfase na importância de se proseguir com a investigaçäo sempre que houver uma forte suspeita clínica, mesmo que os exames iniciais se apresentem dentro dos limites da normalidade.
