Protein secretion by the mouse blastocyst: Stimulatory effect on secretion into the blastocoel by transforming growth factor-α

We have previously demonstrated that newly synthesized proteins are secreted into the mouse blastocoel [Dardik and Schultz (1991): Biol Reprod 45:328–333]. In the present study we examine the effect of transforming growth factor‐α (TGF‐α) on these proteins. We observe that TGF‐α stimulates secretion of these newly synthesized proteins into the blastocoel and apical medium, which faces the zona pellucida, by about 65%. Although one‐dimensional gel electrophoretic analysis does not reveal any marked differences in the patterns of newly synthesized proteins secreted into the blastocoel in response to TGF‐α, zymography reveals a marked stimulation in the secretion of several gelatinases into the blastocoel and apical medium. These results suggest additional functions for TGF‐α in mouse preimplantation development. © 1993 Wiley‐Liss, Inc.