Beta Cell

 (β cell) are a type of cell found in pancreatic islets that synthesize and secrete insulin. Beta cells make up 50-70% of the cells in human pancreatic islets. In patients with type I or type II diabetes, beta-cell mass and function are diminished, leading to insufficient insulin secretion and hyperglycemia.

He decided to hang himself with his colleague because he can't fulfill the overloaded insulin request.