Possible role of endogenous histamine in mediation of LPS-induced secretion of corticosterone in mice.

Escherichia coli lipopolysaccharide (LPS) induced a strong secretion of corticosterone in C3H/HeN mice with a concomitant increase in the splenic histidine decarboxylase activity. Treatment of the mice with alpha-fluoromethyl histidine, a suicide substrate for the enzyme, markedly attenuated both the secretion and the increase. In C3H/HeJ mice, LPS provoked little corticosterone release and induction of the enzyme. However, these mice responded to tetradecanoyl phorbol acetate with a large increase in both this secretion and enzyme activity. Injection of LPS produced a comparable increase in the serum histamine and corticosterone level and activity of histidine decarboxylase in various tissues of genetically mast-cell-deficient W/WV mice and in closely related +/+ mice. These results suggest that secretion of corticosterone caused by LPS is mediated by histamine produced through induction of histidine decarboxylase in non-mast cells.