Effect of insulin-like growth factor-I on protein synthesis in porcine embryonic discs cultured in vitro.
Porcine embryos at Day 13 (Day 0 = first day of oestrus) were collected surgically and embryonic discs were isolated microsurgically. The discs were washed and cultured in Dulbecco's modified Eagle's medium without serum, with either 14C-leucine alone or 14C-leucine plus insulin-like growth factor-I (IGF-I) (100 ng/ml) at 37 degrees C for 48 h in 5% CO2 in air. After incubation, discs were morphologically evaluated, frozen in liquid nitrogen and stored at -70 degrees C. No statistical differences in morphology were observed between embryonic discs cultured in medium with IGF-I and those cultured in medium alone (control). Although more radioactivity was incorporated by embryonic discs in the presence of IGF-I than by those cultured in medium without the growth factor, the difference between the two groups was not significant. From two-dimensional gel electrophoresis, it was observed that IGF-I selectively stimulated the synthesis of four new proteins with Mr of 24,000, 70,000, 77,000 and 95,000, respectively and pI between 5.5 and 6.5. At least 90% of the other proteins in the gels was synthesized in greater amount by embryonic discs cultured in the presence of IGF-I than in the controls. These results show that IGF-I can stimulate protein synthesis in pig embryonic discs cultured in vitro and suggest that this growth factor may play an important role in regulating early development.
Estrada
J L
JL
Department of Animal Science, North Carolina State University, Raleigh 27695-7621.
Jones
E E
EE
Johnson
B H
BH
Petters
R M
RM
D000818:Animals; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D004622:Embryo, Mammalian / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011506:Proteins / Q000032:analysis; D013552:Swine / Q000196:embryology* / Q000378:metabolism
D011506:Proteins; D007334:Insulin-Like Growth Factor I