Abstract: In vertebrates, non-lens bg-crystallins are widely expressed in various tissues and their functions are not well known. The molecular mechanisms of trefoil factors (TFFs), which involved in mucosal healing and tumorigenesis, have remained elusive. bg-CAT is a novel multifunctional protein complex of non-lens bg-crystallin and trefoil factor from frog skin secretions. Here we report that bg-CAT could induce sustained contraction of isolated rabbit aortic rings in dosage (2-35 nmol/L) and endothelium dependent manners (P<0.01). In addition, in situ immunofluorescence indicated that positive TNF-a signals were mainly detected at the endothelial cell layer of bg-CAT (25 nmol/L) treated rings. Furthermore，bg-CAT induced primary cultured rabbit thoracic aortic endothelial cells (RAECs) rapidly to release TNF-a. After bg-CAT (25 nmol/L) treated for 10 and 30 min, the levels of the endothelial cells released TNF-a were 34.17