Changes in glucagon secretion induced by food intake in fulminant type 1 diabetes mellitus: a case report.

Fulminant type 1 diabetes mellitus (FT1DM) is a subtype of type 1 diabetes mellitus and is characterized by a remarkably abrupt onset and almost complete destruction of β-cells within a few days. Here, we report a case of diabetic ketoacidosis in a 63-year-old man with no history of hyperglycemia. The patient was diagnosed with FT1DM and had almost no insulin secretion. We examined his insulin and glucagon secretions induced by a liquid meal test at the onset of FT1DM and 1 year later. The results suggested severely attenuated insulin secretion and an undetectable level of serum insulin 1 year after onset. In contrast, glucagon secretion, which was highly impaired at onset, increased in response to food intake. Although previous reports have suggested that both β- and α-cells of pancreatic islets are damaged in patients with FT1DM, the number of α-cells may increase over time after the onset of FT1DM. © The Japan Diabetes Society 2021.