The effects of furosemide and bumetanide on immunologically stimulated
rat peritoneal and human lung mast cells were compared. Furosemide an
d bumetanide had different modulatory actions on the rat peritoneal ma
st cell. Furosemide inhibited anti-IgE-induced histamine release. Prei
ncubation of the cells with the drug, prior to anti-IgE stimulation, s
ignificantly reduced furosemide's inhibitory effect. In contrast, bume
tanide potentiated anti-IgE-induced histamine secretion from the rat p
eritoneal mast cell. Both diuretics were modest inhibitors of anti-IgE
-mediated histamine release from human lung mast cells. For furosemide
, inhibition decreased with preincubation, while preincubation increas
ed bumetanide's inhibitory action.