To elucidate the mechanism of proinsulin induction by glucose, we determined the amount of proinsulin messenger ribonucleic acid (mRNA), the subcellular distribution of proinsulin mRNA and the transcriptional activity of proinsulin gene in isolated pancreatic islets of rat. From these results, we concluded that the stimulation of proinsulin synthesis was mainly regulated at the translational level. To elucidate the primary structure of vasoactive intestinal peptide (VIP) precursor, we determined the nucleotide sequence of VIP complementary deoxyribonucleic acid (cDNA). The entire amino acid sequence of the VIP precursor indicates that the precursor protein contains not only VIP but also PHI-like peptide. We also found that the induction of pro-VIP synthesis was achieved by enhancing the transcription rate of VIP gene. We also isolated fibroblast growth factor (FGF) receptor cDNA. The nucleotide sequence of FGF receptor cDNA indicates that the receptor is a transmembrane protein that contains extracellular immunoglobulin-like domains and an intracellular tyrosine kinase domain. We also found that the receptor had two isoforms of the extracellular domains and that the expression of the isoforms was regulated tissue-specifically.