930364.fig.001
Figure 1: Genomic and mRNA variants of the rat IGF-1 gene. Exons are shown as boxes and introns as lines. IGF-1A lacks exon 5, while IGF-1B contains exon 5. Transcription of IGF-1A and IGF-1B may begin from within either of promoter 1 (P1) or promoter 2 (P2).