Production of mouse placental lactogen-I by trophoblast giant cells in utero and in vitro.
Mouse placental lactogen-I (mPL-I) is the earliest appearing member of the PRL-GH family of placental hormones. Using immunological techniques, we have localized mPL-I both in utero and in vitro to trophoblast giant cells. Detectable amounts of mPL-I were first seen by immunohistochemistry on day 6 of gestation in the mural trophoblast. On day 7 giant cells of the ectoplacental cone also contained mPL-I, and on day 10 giant cells adjacent to both the decidua basalis and decidua capsularis stained positive. By day 12 however, all intra- and extraembryonic tissues were negative. The pattern of mPL-I staining in the placenta is consistent with its reported gestational serum profile. mPL-I was also present in trophoblast giant cells in vitro shortly after attachment and spreading of day 5 blastocysts. Analysis of conditioned medium from blastocyst outgrowths by immunoprecipitation and two-dimensional electrophoresis, and by immunoblotting, identified mPL-I as the major secretory product from the trophoblast, consisting of a group of acidic proteins of 30,000-45,000 Mr. The synthesis and secretion of mPL-I in vitro occurred in a serum-free medium suggesting that production of this hormone is part of an endogenous program of trophoblast differentiation.
Nieder
G L
GL
Department of Anatomy, Wright State University School of Medicine, Dayton, Ohio 45435.
Jennes
L
L
D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D046508:Culture Techniques; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005865:Gestational Age; D007150:Immunohistochemistry; D051379:Mice; D008813:Mice, Inbred ICR; D008970:Molecular Weight; D010928:Placental Lactogen / Q000096:biosynthesis*; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism*
D010928:Placental Lactogen