Epidermal growth factor and insulin-like growth factor-I stimulate the hydrolysis of the insulin-sensitive phosphatidylinositol-glycan in BC3H-1 myocytes

1988 ◽  
Vol 156 (3) ◽  
pp. 1346-1352 ◽  
Author(s):  
Robert V. Farese ◽  
Govindan P. Nair ◽  
Mary L. Standaert ◽  
Denise R. Cooper
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Epidermal Growth ◽  
Growth Factor I ◽  
Hydrolysis Of

Receptors for epidermal growth factor and insulin-like growth factor-I on preimplantation trophoderm of the pig

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 221-227
Author(s):  
A.N. Corps ◽  
D.R. Brigstock ◽  
C.J. Littlewood ◽  
K.D. Brown
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Molecular Mass ◽  
Cross Linking ◽  
Relative Molecular Mass ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Epidermal Growth ◽  
Growth Factor I

125I-labelled epidermal growth factor (125I-EGF) and 125I-labelled insulin-like growth factor-I (125I-IGF-I) bound to trophoderm cells from pig blastocysts obtained on days 15–19 of pregnancy. Specific binding was detected on freshly isolated cell suspensions and on cells cultured for several days. The binding of 125I-EGF was inhibited by increasing concentrations of EGF, but not by various other growth factors and hormones. Chemical cross-linking of 125I-EGF to its receptors using disuccinimidyl suberate (DSS) revealed a radiolabelled band of relative molecular mass 160,000, similar to that identified as the EGF receptor in other cell types. The binding of 125I-IGF-I was inhibited by both IGF-I and insulin, indicating that the receptors were either type I IGF receptors or insulin receptors. Cross-linking of 125I-IGF-I to serum-free supernatants from trophoderm cultures showed that the cells secreted an IGF-binding protein, giving a complex of relative molecular mass about 45,000. The presence of receptors for EGF and IGF/insulin suggests that these factors could be involved in regulating the growth and development of the early blastocyst.

Changes in protein metabolism of ovine primary muscle cultures on treatment with growth hormone, insulin, insulin-like growth factor I or epidermal growth factor

1987 ◽  
Vol 112 (1) ◽  
pp. 87-96 ◽  
Author(s):  
J. M. M. Harper ◽  
J. B. Soar ◽  
P. J. Buttery
Keyword(s):  
Growth Hormone ◽  
Protein Synthesis ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Muscle Cultures ◽  
Epidermal Growth ◽  
Growth Factor I ◽  
High Concentrations

ABSTRACT Methods for the primary culture of muscle cells from fetal sheep were developed which gave high yields of cells. Myoblasts were grown in vitro, and allowed to fuse to form contractile multinucleate myotubes; these could be maintained in a good condition for at least 2 weeks. Protein turnover in these differentiated cultures was examined for sensitivity to each of four potentially anabolic peptide hormones and growth factors: insulin, insulin-like growth factor I (somatomedin C), epidermal growth factor and growth hormone. Insulin was found to have no effect except at high concentrations (1 μmol/l), compatible with its role as a somatomedin analogue. Insulin-like growth factor I was active at lower levels (1 nmol/l) but the cultures were not as responsive to it as were primary rat muscle cultures or differentiated L6 cells, which were tested in similar experiments. The maximum stimulation of protein synthesis observed with the ruminant system was only 16%. Epidermal growth factor was highly anabolic for primary cultures from sheep muscle, and the cells were very sensitive to it, half-maximal stimulation of protein synthesis being seen with concentrations as low as 20 pmol/l. No effects of bovine growth hormone were seen in the ovine system. However, an inhibition of protein breakdown was found with high concentrations (0·1 μmol/l) in the L6 rat myoblast cell line. It was found that the culture conditions used could affect the observed responses of protein synthesis and degradation, despite withdrawal of serum from the incubation media 22 h before testing. J. Endocr. (1987) 112, 87–96

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