INS and type 1 diabetes mellitus: On average for 18 biological batches (9 for T1D and 9 for ND), T1D and ND SC-β cells secrete 2.0±0.4 and 1.9±0.3 μIU of human insulin per 103 cells in response to 20 mM glucose and have stimulation indexes (ratio of insulin released at 20–2 mM glucose) of 1.9 and 2.2, respectively (Fig. 1f).