Insulin-like growth factor-I binds in the inner plexiform layer and circumferential germinal zone in the retina of the goldfish.
Results of the previous study suggest that insulin-related peptides regulate proliferation of retinal progenitors in the adult goldfish. Because of their known roles in retinal neurogenesis, we have chosen to focus future studies on insulin-like growth factor I (IGF-I) and the IGF-I receptor. In the study described here, we characterized the spatial distribution and specificity of IGF-I binding sites in the retina of the adult goldfish by performing receptor-binding autoradiography with [125I]-IGF-I alone and with unlabeled IGF-I-related molecules (IGF-I, IGF-II, insulin, and des-[1-3]-IGF-I) as competitive inhibitors of [125I]-IGF-I binding. The results of these experiments show that IGF-I binds in two locations in the retina of the adult goldfish, within the inner plexiform layer of the differentiated retina and the circumferential germinal zone. The competition experiments suggest that [125I]-IGF-I binds at sites specific for IGF-I, and that both IGF-I receptors and IGF-I binding proteins are present in the retina.
Boucher
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SE
The Neuroscience Program, The University of Michigan, Ann Arbor 48105, USA.
Hitchcock
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PF
D000818:Animals; D001345:Autoradiography; D006054:Goldfish / Q000033:anatomy & histology / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D008938:Mitosis / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D011869:Radioligand Assay; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism
D018969:Insulin-Like Growth Factor Binding Proteins; D010446:Peptide Fragments; C058957:insulin-like growth factor 1, des-(1-3)-; D007334:Insulin-Like Growth Factor I