Apoptosis/physiology; Insulin/metabolism; Neurons/metabolism; Retina/growth & development; Retina/metabolism; Transforming Growth Factor beta/metabolism; Animals; Animals, Newborn; Apoptosis/drug effects; Caspase 3; Caspases/genetics; Caspases/metabolism; Cell Differentiation/drug effects; Cell Differentiation/physiology; Cells, Cultured; DNA-Binding Proteins/drug effects; DNA-Binding Proteins/genetics; DNA-Binding Proteins/metabolism; Down-Regulation/drug effects; Down-Regulation/physiology; Drug Interactions/physiology; Gene Expression Regulation, Developmental/drug effects; Gene Expression Regulation, Developmental/genetics; Insulin/pharmacology; Mice; Mice, Inbred C57BL; Neurons/drug effects; Organ Culture Techniques; Organogenesis/drug effects; Organogenesis/physiology; Phosphorylation/drug effects; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-bcl-2/genetics; Proto-Oncogene Proteins c-bcl-2/metabolism; RNA, Messenger/drug effects; RNA, Messenger/metabolism; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta/drug effects; Receptors, Transforming Growth Factor beta/genetics; Receptors, Transforming Growth Factor beta/metabolism; Retina/drug effects; Smad Proteins; Trans-Activators/drug effects; Trans-Activators/genetics; Trans-Activators/metabolism; Transcription Factors/genetics; Transcription Factors/metabolism; Transcriptional Activation/drug effects; Transcriptional Activation/genetics; Transforming Growth Factor beta/pharmacology; Up-Regulation/drug effects; Up-Regulation/physiology