THE EFFECT OF THEOPHYLLINE ON THE PRODUCTION OF COLONY STIMULATING FACTOR (CSF)BY THE LUNG

The effect of theophylline on colony stimulating factor production by the lung tissue was investigated. Addition of various concentrations of theophylline to the lung conditioned medium enhanced CSF production at 10 µg/ml and at higher concentrations showed an inhibitory effect. Determination of the phosphate content of the medium showed a decrease at 1-3 hours of incubation. Addition of AMP to the cultures in the presence of theophylline had no effect on the CSF production but compensated phosphate content of the lung cultures. Exogenous cAMP or its dibutyryl derivative also stimulated CSF production. On the other hand IBMX, another inhibitor of phosphodiesterases, exerted similar effect as theophylline. The results suggest that cAMP regulates CSF production by the lung.