Tryptophan and kynurenine stimulate human decidualization via activating Aryl hydrocarbon receptor: Short title: Kynurenine action on human decidualization.

Decidualization is essential for successful pregnancy in rodents and primates. Although L-Tryptophan and its metabolites are essential for mammalian pregnancy, the underlying mechanism is poorly defined. We explored effects of tryptophan and kynurenine on human in vitro decidualization in human endometrial stromal cell line and primary endometrial stromal cells.