Characterization of stable INS1E clones overexpressing hIAPP and rIAPP. Cells were routinely cultured in RPMI medium at 11.1 mm glucose. A, hIAPP mRNA levels of stable INS1E clones were detected by real-time PCR. The data were normalized to GAPDH mRNA and presented as relative to the hIAPP1 cells *, p < 0.05 versus hIAPP1 cells (n = 3–5). B, specificity of hIAPP immunostaining. Immunodetection of hIAPP in control cells and hIAPP cells (×40); IAPP immunostaining is detected in the cytoplasm. Bar is 50 μm. C, rIAPP mRNA levels of stable INS1E clones were detected by real-time PCR. The data were normalized to GAPDH mRNA and presented as relative to control cells *, p < 0.05 versus control cells (n = 3–5). D, total IAPP content was measured by ELISA assay in cells cultured in routine culture medium (11.1 mm). *, p < 0.05 versus control cells (n = 4). Results are expressed as mean ± S.E.