.

There is a multisided connections between the thyroid gland and the respiratory system. Thyroid gland is closely localized to trachea by anatomic situation and either thyroid gland or trachea functions by oxidative metabolism. Thyroid hormones probably play an important role in the development of the lung(6-10). Some of the changes occur with hypothyroid and hyperthyroid situations in the respiratory system (6, 11-20). In hyperthyroid cases, oxygen consumption, C02 production, ventilation and respiration number increase where vital capacity, CO diffusion capacity and respiratory muscle weakness decrease (6, 17-20). Dyspnea is a frequent complaint within hypothyroid patients (3,4, 11, 12,22,23). Decreased maximum respiration capacity, diffusion capacity and decreased respiration response to carbondioxide can be observed (24) Changes in the respiration system are not completely known in subclinic hypothyroid cases (1,4, 12). Our objective in the study was to research the changes within respiration system in the patients diagnosed as subclinic hypothyroid situations before and after the thyroid hormone replacement therapy. Respiration function tests of 38 patients (1 male, 37 female) were done before the thyroid hormone replacement therapy who were diagnosed as subclinic hypothyroid situations. These patients included our study and they were all referred to our polyclinics of Endocrinology and Metabolism Diseases Department of internal Medicine mainscience between February 2003 - June 2004 in Celal Bayar University research and application hospital. Later, blood samples for artery blood gases were taken from each participants. Then bronchial provacation (37 cases) and reversibility (1 case) tests were applied. In our therapeutic procedure , all subclinic hypothyroid patients of the study took appropiate doses of Levotiron® tabletes daily (in morning fasting) for average 6-8 weeks. After this application, thyroid function tests were observed. Respiratory function tests and artery blood gases analysis of the patients were repeated who become euthyroid situations. As a result, there was no statistical significance in respiration function tests after the treatment in accordance with the pre-treatment situations [FEV1 (p=0.36), FVC (p=0.084), FEV1/FVC (p=0.53)] (Table 15). There was no statistical significant difference in the values of p02 (p=0.64) and pC02 (p=0.84) in artery blood gases 49 analysis. However, there was statistical significant increase in 0 2 saturation values after the treatment in accordance with the pre-treatment situations (p<0.011 ); but this increase was within normal limits (Table 13).