SLC5A1 and cystic fibrosis: We discovered that SGLT1 was universally upregulated in all these tissues in the CF-9 rabbits (Figure 1, A–C), as well as in those of CF rabbits carrying different CFTR mutations, which include a CF-1 line that mimics a class I null mutation (11) and the recently developed CFTR-F508del line (12) that represents the most dominant patient mutation (Supplemental Figure 1, A and B; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.165826DS1).