title: 3H-uridine incorporation in early porcine embryos.
abstract: The present study investigated the ontogeny of 3H-uridine incorporation into RNA as a measure for RNA synthesis in preimplantation porcine embryos from the two-cell stage up to the stage of the newly hatched blastocyst. A total of 568 embryos were cultured in vitro for 3 hr in medium (KRB plus lamb serum) containing 9 microM 3H-uridine. After disruption of cell membranes, RNA was isolated on DEAE cellulose filters, and the radioactivity was taken as a measure for the rate of RNA synthesis. No RNA synthesis was detected at the two-cell stage. From the four-cell to the morula stage, 3H-uridine incorporation per embryo increased about ninefold (P less than 0.001); in blastocyst stages, the increase between developmental stages was not statistically significant. Hatched blastocysts had the highest genomic activity. On a per cell basis, 3H-uridine incorporation was not different from the four-cell stage up to the zona pellucida-intact blastocyst and amounted to 0.29-0.37 fmol 3H-uridine incorporation/cell/3 hr. In hatched blastocysts, 3H-uridine incorporation per blastomere was increased (P less than 0.01 compared with younger stages) and amounted to 0.86 fmol 3H-uridine incorporation/cell/3 hr. It is concluded that 1) the rate of uridine incorporation depends on the cell stage in zona pellucida-intact porcine embryos and 2) uridine incorporation per blastomere is significantly increased in hatched blastocysts compared with earlier stages.
authors.affiliation: Institut für Tierzucht und Tierverhalten (FAL), Mariensee, Neustadt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Freitag
authors.forename: H H
authors.initials: HH
authors.lastname: Döpke
authors.forename: H
authors.initials: H
authors.lastname: Niemann
authors.forename: F
authors.initials: F
authors.lastname: Elsaesser
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002478:Cells, Cultured; D002970:Cleavage Stage, Ovum / Q000378:metabolism; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D011247:Pregnancy; D012313:RNA / Q000096:biosynthesis*; D013552:Swine; D014529:Uridine / Q000378:metabolism*
chemical_list: D012313:RNA; D014529:Uridine