The effect of theophylline on macrophage elastase secretion.

Theophylline increased the elastolytic activity in conditioned media from murine peritoneal macrophages maintained in a monolayer system. Continuing accumulation of enzyme activity with time required the continuing presence of the drug. Theophylline was active in the presence of a maximally stimulatory concentration of colchicine, a known enhancer of elastase secretion. The effect of theophylline was not due to interference with any elastase inhibitory activity in macrophage conditioned medium. The elastolytic activity from theophylline-stimulated cells exhibited an inhibitor profile similar to the profiles of colchicine-stimulated and unstimulated cells. The results demonstrate that theophylline regulates the amount of extracellular elastolytic activity from murine peritoneal macrophages differently from granulocytic elastase.