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.
Department of Animal Science, North Carolina State University, Raleigh 27695-7621.
J L
JL
Estrada
E E
EE
Jones
B H
BH
Johnson
R M
RM
Petters
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