Deciduoma Formation in Uterus of Genetically Mast Cell-Deficient W/Wv Mice1

The role of mast cells in deciduoma formation in the uterus of mice was investigated by using genetically mast cell-deficient (WB x C57BL/6)F1-W/Wv (hereafter called WBB6F1-W/Wv) mice. Deciduoma formation occurred in castrated WBB6F1-W/Wv mice after estradiol-progesterone injection and traumatization in spite of their deficiency of mast cells. Injection of diphenhydramine, which blocks histamine receptors, inhibited deciduoma formation in WBB6F1-W/Wv mice as well as in congenic +/+ mice. THe uterus of WBB6F1-W/Wv mice contained about 10% of the amount of histamine found in the uterus of +/+ mice. These results suggest that mast cells are not essential for formation of deciduomata and that histamine originating from sources other than mast cells may be important in deciduoma formation.