INS and diabetes mellitus: For example, in ~500 HF/HS-fed DO mice, Keller and colleagues identified genetic variants in pancreatic islets associated with diabetes-related traits in vivo, including plasma insulin and glucose levels following fasting, or in response to an oral glucose tolerance test (Keller et al., 2018), and in cultured islets treated ex vivo with insulin secretagogues (Keller et al., 2019), as previously mentioned.