In vitro chronic glucolipotoxicity reduces insulin docking and exocytosis. Rat islets were cultured under normal conditions (control) or with 16.7 mM glucose and 500 μM palmitate for 72 h (GL). Post 72 h, RNA was isolated from islets and the mRNA levels of Rab27a (A) were measured as described in the materials and methods. For measurement of insulin granule docking (B) following incubation under chronic glucolipotoxic conditions, islets were treated with LG (2.5 mM glucose) with or without 30 mM KCl for 30 min. Secreted insulin was measured as described in the materials and methods. Data are expressed as mean±SEM and statistical analysis was performed using the unpaired Student’s t-test. (*P<0.05, **P<0.01 and ***P<0.001, n=4).