Inhibition of mast-cell degranulation by chemotactic peptides

Pepstatin and f-methionyl peptides which are potent chemotactic agents for neutrophils were found to inhibit the increase in vascular permeability of rat skin which follows the injection of 48/80, anti-rat IgE serum, or pulmonary permeability factor. These latter compounds are known to act by releasing histamine from mast cells. f-Met-Leu-Phe, which is the most active chemotactically, was also found to be the most active inhibitor.