Isoelectric analysis of respiratory mucus from normal rats and rats exposed to tobacco smoke.

Various functions of the pulmonary defense mechanism, such as ciliary beat and mucous transportation, and free lung cells have been studied in many experiments. The protein composition of the bronchial mucus and its viscosity, however, have been the subjects of few investigations. We have used an isoelectric focusing technique for protein separation and estimated a total error of measurement (variation between animals and residual error) to compare the bronchial mucus of normal control rats and rats exposed to tobacco smoke. Significant differences in the composition of the mucus were found; in addition, the composition of serum differed in some respects. The isoelectric focusing technique can be useful for protein analysis of bronchial mucus.