Autophagy in beta cells has been demonstrated to play a pivotal role in cellular homeostasis and the progression of glucose intolerance. Although autophagic activity is affected by metabolic stress both in vivo and in vitro, it remains unclear as to what extent the autophagic status in each beta cell is different from its neighboring cells. To address this question, GFP-LC3 reporter mice, which can visualize the autophagic status of each beta cell as green-fluorescent puncta, were crossed with obese diabetic db/db mice. Imaging of green fluorescent puncta in the islets of GFP-LC3 mice revealed that beta cells are a heterogeneous population, as the density of GFP-LC3 puncta in each cell was variable. Furthermore, the variability was greater in GFP-LO; db/db mice than in non-diabetic GFP-LC3; db/+ mice. Furthermore, when GFP-LC3 mice were treated with a low dose of 5961, which antagonizes insulin signaling without inducing overt hyperglycemia, the number of beta cells with a high density of GFP puncta was increased, suggesting that insulin resistance affects autophagic status independently of glucose profiles. These results suggest that pancreatic beta cells under metabolic stress are heterogeneous regarding their autophagic status, which provides insights into the cellular dynamics of each beta cell rather than the whole beta-cell population. (C) 2018 Elsevier Inc. All rights reserved.