We have examined biochemical and functional characteristics of dispersed sinus mast cells and compared them with those of mast cells dispersed from other tissues. This experiment yielded the following results. 1) Although no difference was observed in histamine content, tryptase content in sinus mast cells was significantly lower than that of skin and lung mast cells. 2) In contrast with the situation in foreskin mast cells, anti-IgE-induced histamine release from sinus and lung mast cells was potentiated with lower concentrations of adenosine. 3) Similar to lung mast cells, sinus mast cells did not respond to compound 48/80 or substance P, whereas skin mast cells were stimulated to release histamine with either 10 micrograms/ml of compound 48/80 (14.0%) or 10(-4) M of substance P (23.4%). 4) Sinus mast cells are similar to lung mast cells in terms of release of arachidonic acid metabolites. Anti-IgE challenge of sinus mast cells caused the generation of both prostaglandin D2 (89.5 +/- 33.7 ng/10(6) mast cells, n = 14) and i-leukotriene D4 (78.7 +/- 46.8 ng/10(6) mast cells, n = 10).