Islet cell ER stress assay

8-week-old female NOD.scid mice were given drinking water with or without pargyline (5 μg/ml) ad libitum for 1 week. Islets were prepared and purified as described above. Purified NOD.scid islets were cultured in a low-attachment plate in full culture media with or without pargyline (2 μg/ml) with or without 1 μM thapsigargin for 5 h. Islet protein samples were collected as described below (see Western blotting). 20 μg denatured islet proteins were used for SDS-PAGE electrophoresis. Cleaved Caspase-3 (Cell signaling, #9664S) and GAPDH (Cell signaling, #2118) were blotted to detect apoptotic pathway activation.