The effect of thyroid hormone on generation of free radicals by neutrophils and alveolar macrophages.

We have sometimes observed the case of bronchial asthma accompanied by hyperthyroidism. But the pathophysiological mechanisms of both diseases remain obscure. In this study, we have shown that thyroid hormone directly stimulated the generation of superoxide anion by neutrophils and alveolar macrophages. In addition, neutrophils incubated with thyroid hormone became activated and generated greater amount of superoxide anion in response to f-met-leu-phe (fMLP) and phorbol myristate acetate (PMA). Our study suggests, for the first time, that reactive oxygen species may play one of the most important roles in exacerbating asthma in hyperthyroid patients.