In contrast, glucose cycling studies in INS1-832/13 cells (Figs. 1B and S1, B, D, and F), a rat insulinoma cell line, showed negligible glucose cycling (≤3%) and net release of glucose (Fig. S1F, ∼1 nmol/106 cells/hr), further validating that G6pc2 is a pseudogene in rats (11). This evidence concerns the gene G6PC2 and pancreatic insulinoma.