Bassas L, Lesniak M A, Serrano J, Roth J, de Pablo F
Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
Diabetes. 1988 May;37(5):637-44. doi: 10.2337/diab.37.5.637.
Chicken embryos are a suitable model for studying the role of insulin, insulin-like growth factors I and II (IGF-I and IGF-II), and their receptors in embryogenesis. We show that plasma membranes from heart, liver, and limb buds, as reported earlier for brain, each have a distinct developmental profile for insulin receptors and type I IGF receptors. In heart and limb buds, IGF binding is higher than insulin binding, but in liver, insulin receptors dominate. Expression of these receptors is, therefore, developmentally regulated and tissue specific. The wide distribution of high-affinity receptors capable of mediating insulin and IGF actions in early organogenesis further supports the possible importance of this family of peptides for differentiation and growth in vertebrates. In all chicken embryo tissues studied, both IGF-I and IGF-II appeared to bind to a type I IGF receptor. We have not detected a receptor with the peptide binding and structural characteristics of the mammalian type II IGF receptor. The type II receptor was absent in embryos, liver from newly hatched chicks, and adipocytes from older chicks, which suggests that the chicken may lack this subtype of IGF receptor.
鸡胚是研究胰岛素、胰岛素样生长因子I和II（IGF-I和IGF-II）及其受体在胚胎发生中作用的合适模型。我们发现，如先前关于脑的报道，心脏、肝脏和肢芽的质膜对于胰岛素受体和I型IGF受体各自具有独特的发育特征。在心脏和肢芽中，IGF结合高于胰岛素结合，但在肝脏中，胰岛素受体占主导。因此，这些受体的表达受发育调控且具有组织特异性。在早期器官发生中能够介导胰岛素和IGF作用的高亲和力受体的广泛分布，进一步支持了这一族肽对于脊椎动物分化和生长可能具有的重要性。在所有研究的鸡胚组织中，IGF-I和IGF-II似乎都与I型IGF受体结合。我们未检测到具有哺乳动物II型IGF受体肽结合和结构特征的受体。II型受体在胚胎、新孵出雏鸡的肝脏以及大龄雏鸡的脂肪细胞中均不存在，这表明鸡可能缺乏这种IGF受体亚型。
