Chick embryo retina development in vitro: the effect of insulin.
In this paper we study the development of chick embryo retina cultured in vitro and the effects exerted by insulin. Retinas were removed from 7-day embryos and cultured in serum- and hormone-free medium for 7 additional days. Under these conditions retinal cells survived and underwent cholinergic differentiation, as previously ascertained by Hausman et al. (Dev. Brain Res., 1991, 59: 31-37). However, a great retardation of development was noted compared to uncultured control, 14-day retina. In fact both wet weight and DNA and protein content increased much slower than in ovo and the tubulin content decreased below even the starting value. In addition, although after 7 days in culture retinal cells were organized in identifiable layers, nevertheless the typical organization equivalent to 14-day in ovo retina was absent. The addition of insulin in the medium markedly increased the wet weight of cultured retinas, their protein content and the level of tubulin pools, particularly that of non-assembled fraction. Nevertheless insulin did not modify DNA synthesis and did not induce the increment of both neuron specific enolase and actin. Morphological observations show that insulin markedly increased the number and the thickening of the fiber layers. These results, together with the facts that retina synthesizes and secretes insulin and possesses specific insulin receptors suggest that insulin can have autocrine or paracrine regulatory functions in retinal development by exerting a general effect on retinal growth and a more specific one on tubulin production.
D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D002642:Chick Embryo; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D016895:Culture Media, Serum-Free; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D009924:Organ Culture Techniques; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D014176:Protein Biosynthesis; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism
D016895:Culture Media, Serum-Free; D007328:Insulin; D014404:Tubulin; D004247:DNA; D002795:Choline O-Acetyltransferase; D001219:Aspartate Aminotransferases; D010751:Phosphopyruvate Hydratase; D007930:Leucine; D013936:Thymidine