Insulin and glucagon hormones were detected in paraffin sections (4 \u03bcm thickness) of formalin-fixed human pancreases. Insulin and glucagon were detected immunohistochemically using mouse anti-human insulin mAb (ascites; Sigma) and mouse anti-porcine glucagon mAb (ascites; Sigma), respectively, with biotinylated anti-mouse IgG and avidin-biotin-complex (ABC reagent; PK-2200, Vector Labs). Background staining was checked using the corresponding isotype control Ig instead of the primary antibody. 3-amino-9-ethylcarbazole (AEC) was used as the chromogen. Stained sections were imaged using a light microscope with attached camera (Olympus BX41).