Hydrocortisone inhibits phorbol ester stimulated release of histamine and arachidonic acid from rat mast cells.

Purified rat peritoneal mast cells were incubated overnight with or without hydrocortisone (3 X 10(-6) M) and then stimulated with anti-IgE, somatostatin or a phorbol ester-ionophore combination, i.e., 12-O-tetradecanoyl-phorbol-13-acetate and A23187. The release of both histamine and [1-14C]arachidonic acid and its metabolites was determined. Hydrocortisone treatment markedly inhibited both anti-IgE and TPA-A23187 stimulated release, but not release stimulated by somatostatin. These results suggest that anti-inflammatory steroids may alter histamine release through an action involving the activation of the phosphatidylserine-calcium dependent protein kinase or its substrates.