Insulin family growth factors have specific effects on protein synthesis in preimplantation mouse embryos.
Previously constructed protein databases for two stages of preimplantation mouse embryogenesis, the compacted eight-cell stage and the fully expanded blastocyst stage, have been used to analyze the effects of insulin, IGF-I, and IGF-II on protein synthesis in these developmental stages. Proteins were labeled by placing, for 2 hr, synchronous cohorts of 35-50 embryos into human tubal fluid (HTF) medium containing L-[35S]-methionine (1 mCi/ml) in the presence or absence of one of the growth factors. The embryos were then washed with medium and lysed. Samples were processed for 2-D gel analysis. For each embryonic stage and each growth factor, four or five experimental replicates were done and the gel images were compared using the PDQUEST system. Using the computer-assisted analysis, we were able to identify proteins that showed a statistically significant (P < 0.05) change in synthesis. At the eight-cell stage of development insulin caused increased synthesis of two proteins and decreased synthesis in three proteins. Insulin-treated blastocyst stage embryos exhibited an increased synthesis in eight proteins and decreased synthesis for one protein. The effect of IGF-I at the eight-cell stage of development was mostly inhibitory; the synthesis of only one protein increased and the synthesis of five proteins showed a decrease. Similar results were obtained with blastocyst stage embryos; four proteins demonstrated an increase in synthesis while 14 proteins showed a decrease. Eight-cell stage embryos incubated with IGF-II had seven proteins with a decreased synthesis, although in blastocyst stage embryos, nine proteins showed increased synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)
Shi
C Z
CZ
Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia.
Collins
H W
HW
Buettger
C W
CW
Garside
W T
WT
Matschinsky
F M
FM
Heyner
S
S
D000818:Animals; D001755:Blastocyst / Q000187:drug effects* / Q000378:metabolism; D002970:Cleavage Stage, Ovum / Q000187:drug effects* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005326:Fetal Proteins / Q000096:biosynthesis*; D005786:Gene Expression Regulation / Q000187:drug effects*; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology*; D051379:Mice
D005326:Fetal Proteins; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II