Journal of Applied Physiology, Vol 58, Issue 5 1485-1488, Copyright © 1985 by American Physiological Society

ARTICLES

Airway reactivity and lung function in triiodothyronine-induced thyrotoxicosis

R. S. Irwin, M. R. Pratter, D. H. Stivers and L. E. Braverman

To evaluate the possible relationship between asthma and hyperthyroidism, airway reactivity and lung function were prospectively compared in healthy volunteers before, during, and after liothyronine (triiodothyronine, T3)-induced hyperthyroidism. Base-line evaluation of the 10 subjects included clinical evaluation, thyroid and pulmonary function tests, and airway reactivity assessed by methacholine inhalational challenge (MIC). All studies were normal. During T3-induced hyperthyroidism, no subject developed respiratory symptoms or changes in pulmonary function or airway reactivity. The mean percent change in forced expiratory volume at 1 s from base line (delta FEV1) of -2.4 +/- 3.0 after MIC was not significantly different from that obtained before T3 administration (-1.4 +/- 1.5, P greater than 0.2). When all serum T3 concentrations and delta FEV1 values before, during and after T3-induced hyperthyroidism were compared, there was no significant correlation. We conclude that T3-induced hyperthyroidism of 3-wk duration has no effect on airway reactivity or lung function in normal volunteers.