β-Cell Obligation in α-Cell Glucagon Response to Low Glucose

Research Overview

Type 1 diabetes destroys insulin-producing β-cells, but patients also face life-threatening hypoglycemia because their α-cells fail to release glucagon when glucose falls — a counterregulatory failure whose cause was poorly understood.

Using human pseudoislets from non-diabetic donors alongside mouse models, the authors showed that α-cells isolated from all other islet cell types cannot mount a glucagon response to low glucose, fully reproducing the diabetic phenotype. Strikingly, even a few β-cells per islet were enough to restore that response. Hypoglycemia-induced glucagon secretion is therefore not an intrinsic α-cell property but depends on β-cell input — reframing defective counterregulation in diabetes as a consequence of β-cell loss itself.