To examine the production of hepatocyte growth factor (HGF) by human endometrial stromal cells (ESC) in vitro, concentrations of HGF in the culture media of ESC were measured after the addition of various amounts of 12-O-tetradecanoylphorbol 13-acetate (TPA), forskolin, lipopolysaccharide (LPS), interleukin (IL)-1 beta, IL-6, IL-8, tumor necrosis factor alpha (TNF alpha), interferon-gamma (IFN gamma), or ethynylestradiol-17 alpha using an ELISA. The expression of HGF mRNA was also assayed by a reverse transcription-polymerase chain reaction. The concentration of HGF in the culture media of unstimulated ESC was below the detection level of the assay. TPA stimulated the secretion of HGF by ESC in a dose-dependent manner. TPA also induced the transcription of HGF mRNA by ESC. Forskolin, LPS, IL-1 beta, IL-6, IL-8, TNF alpha, IFN gamma, or ethynylestradiol-17 alpha did not alter HGF mRNA or protein levels. TPA-stimulated production of HGF was partially inhibited by the addition of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine or sphingosine. These results suggest that a protein kinase C-dependent pathway may play an important role in the regulation of HGF production by ESC. HGF secreted by ESC may be involved in the regeneration of the endometrium during the normal menstrual cycle.