The in vivo effects of prostaglandins E1, E2 and F2 alpha on mucociliary activity in the rabbit maxillary sinus were investigated using a photoelectric technique. Prostaglandins E1 and F2 alpha both accelerated the mucociliary wave frequency in a dose-dependent fashion. For prostaglandin E1 the maximum increase was 17.4 +/- 2.6% (0.1 micrograms/kg), for prostaglandin F2 alpha it was 24.1 +/- 3.0% (10 micrograms/kg). The effects of prostaglandin E2 was inconsistent. Although some doses stimulated mucociliary activity, the effects were not reproducible. Inhibition of phosphodiesterase with theophylline did not alter the response to exogenous prostaglandin E1, nor did inhibition of endogenous prostaglandin synthesis with indomethacin affect the basal mucociliary activity or the response to exogenous prostaglandin E1. The present findings suggest that the tested prostaglandins are of minor importance for regulating mucociliary function in the rabbit maxillary sinus.