Insulin-like growth factor-I and insulin as growth and differentiation factors in chicken embryogenesis.
The avian embryo has been a useful model system for studies on the role of insulin and its close relative insulin-like growth factor-I (IGF-I) in development. The unfertilized chicken egg contains both peptides from maternal origin, and the embryo expresses insulin and IGF-I before the major organs are formed. Insulin receptors and IGF-I receptors are found in the blastoderm and in all tissues examined during organogenesis. When exogenous insulin or IGF-I are added to the embryo, growth and differentiation events are stimulated. By contrast, insulin antibodies and insulin receptor antibodies retard embryo development. In embryos cultured ex ovo, in which growth is impaired, the levels of serum IGF-I are decreased.
De Pablo
F
F
Section on Receptors and Hormone Action, National Center for Research Resources, National Institutes of Health, Bethesda, Maryland 20892.
Robics
H L
HL
Caldés
T
T
Alemany
J
J
Scavo
L
L
Serrano
J
J
D000818:Animals; D002454:Cell Differentiation; D002642:Chick Embryo / Q000166:cytology / Q000254:growth & development*; D007328:Insulin / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D011972:Receptor, Insulin / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis; D017451:Receptors, Somatomedin
D007328:Insulin; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D011972:Receptor, Insulin