DDT and inflammatory responses: 3. Release of histamine from mast cells exposed to DDT

Release of histamine from mast cells by DDT was demonstrated by incubating guinea pig mesentery explants with 20 μg DDT/ml in vitro for various periods up to 2 hr. The histamine content of mesentery explants showed progressive decreases concomitant with increasing histamine values in the incubation medium. In the mesentery explants the histamine content decreased to 31% of the original content within 45 min and then increased to 113% at the 120-min interval. As the total amount of histamine released into the medium during the 2 hr of incubation with DDT was twice the original amount of histamine in the tissues, it is evident that the initial release of histamine by DDT stimulates its resynthesis in the mast cells.