Reinecke M, Broger I, Brun R, Zapf J, Maake C
Division of Neuroendocrinology, University of Zürich, Switzerland.
Gen Comp Endocrinol. 1995 Dec;100(3):385-96. doi: 10.1006/gcen.1995.1169.
Immunoreactive insulin-like growth factors I and II (IGF-I, IGF-II) were sought in the endocrine pancreas of representative birds, reptiles, and amphibia using antisera specific for mammalian IGF-I and IGF-II and the classical islet hormones insulin (INS), glucagon (GLUC), somatostatin (SOM), and pancreatic polypeptide (PP) in double immunofluorescence. Both IGF-I and IGF-II immunoreactivities were present in the endocrine pancreas of all species. IGF-II immunoreactivity was exclusively found in INS-immunoreactive (-IR) cells, indicating evolutionary conservation of the islet IGF-II system. In contrast, IGF-I immunoreactivity was distributed differently among the species and never occurred in INS-IR cells. In the anuran Xenopus laevis, IGF-I immunoreactivity was present in islet cells showing coexistence of GLUC and PP immunoreactivities. In reptiles, the lizards (Lacerta viridis, Scincus officinalis) exhibited IGF-I immunoreactivity in PP-IR and SOM-IR cells and the snakes (Psamophis leniolatum, Coluber ravergieri) in SOM-IR and GLUC-IR cells. In birds, IGF-I immunoreactivity was located either in SOM-IR cells only (Gallus g. domesticus, Streptopelia roseogrisea) or in PP-IR and SOM-IR cells (Coturnix c. japonica). Thus, the distribution patterns of islet IGF-I immunoreactivities in birds, reptiles, and amphibia are equivalent to those in mammals and most bony fish. They differ, however, from those found in cartilaginous fish, cyclostomes, and protochordates, where a total or partial coexistence of IGF-I and INS immunoreactivities has been obtained. Therefore, the divergence of IGF-I and INS seems to have occurred early in vertebrate phylogeny. Furthermore, the existence of IGF-I immunoreactivity likely is common in the islets of all vertebrates. Finally, no phylogenetic trend to concentrate IGF-I immunoreactivity in a particular islet cell type is apparent.
利用针对哺乳动物胰岛素样生长因子I（IGF-I）和胰岛素样生长因子II（IGF-II）的抗血清以及经典胰岛激素胰岛素（INS）、胰高血糖素（GLUC）、生长抑素（SOM）和胰多肽（PP），通过双重免疫荧光法在代表性鸟类、爬行动物和两栖动物的内分泌胰腺中寻找免疫反应性IGF-I和IGF-II。在所有物种的内分泌胰腺中均存在IGF-I和IGF-II免疫反应性。IGF-II免疫反应性仅在INS免疫反应性（-IR）细胞中发现，表明胰岛IGF-II系统具有进化保守性。相比之下，IGF-I免疫反应性在不同物种中的分布不同，且从未出现在INS-IR细胞中。在无尾两栖动物非洲爪蟾中，IGF-I免疫反应性存在于显示GLUC和PP免疫反应性共存的胰岛细胞中。在爬行动物中，蜥蜴（绿蜥蜴、沙鱼）在PP-IR和SOM-IR细胞中表现出IGF-I免疫反应性，而蛇（细纹沙蟒、拉氏锦蛇）在SOM-IR和GLUC-IR细胞中表现出IGF-I免疫反应性。在鸟类中，IGF-I免疫反应性要么仅位于SOM-IR细胞中（家鸡、粉红胸斑鸠），要么位于PP-IR和SOM-IR细胞中（日本鹌鹑）。因此，鸟类、爬行动物和两栖动物中胰岛IGF-I免疫反应性的分布模式与哺乳动物和大多数硬骨鱼中的分布模式相同。然而，它们与软骨鱼、圆口纲动物和原索动物中的分布模式不同，在这些动物中已发现IGF-I和INS免疫反应性完全或部分共存。因此，IGF-I和INS的分化似乎在脊椎动物系统发育的早期就已发生。此外，IGF-I免疫反应性的存在可能在所有脊椎动物的胰岛中都很常见。最后，没有明显的系统发育趋势将IGF-I免疫反应性集中在特定的胰岛细胞类型中。
