Characterization of a plasminogen activator inhibitor induced by glucocorticoids in immature bovine Sertoli cell-enriched cultures

Abstract

ABSTRACT Plasminogen activation has been shown to be inhibited by the cell-specific production of a number of protease inhibitors belonging to the serine protease inhibitor family. In the bovine testis this inhibitor production is induced by glucocorticoids. Monospecific antibodies raised against the three known classes of plasminogen activator inhibitor were used to identify which type of inhibitor was secreted by bovine Sertoli cell-enriched cultures. Immunoblot analysis and [35S]methionine labelling of newly synthesized proteins revealed that a novel protein with an apparent molecular weight of 49 kDa, which shares antigenic determinants with placental and macrophage PAI and fibroblast protease nexin, is secreted in response to dexamethasone stimulation. This protein was shown by immuno-adsorption to be a functionally active inhibitor of both tissue-type and urokinase-type plasminogen activators. J. Endocr. (1988) 117, 69–74