Mast cell histamine, a local mitogen acting via H2-receptors in nearby tissue cells.

The tissue mast cell is the major storage site of histamine in the body. The present study is concerned with the effect of one histamine H1- and one histamine H2-receptor antagonist on proliferation in the rat mesentery following drug-induced mast-cell secretion. The H2-receptor antagonist, but not the H1-receptor antagonist, significantly suppressed mast-cell-mediated proliferation in vivo and in organ-cultured mesentery. This finding indicates that mast-cell-histamine is a mitogen acting directly on histamine H2-receptors in surrounding tissue cells.