MS-0870

A 55-year-old man comes in for his regular check-up with his GP. He has a medical history of chronic pancreatitis and diabetes mellitus and is currently taking the maximum doses of metformin and gliclazide. During a random plasma glucose test, his levels show 18.0 mmol/l and his urinalysis reveals glycosuria with minimal ketones. The GP suspects that his body is not producing enough insulin and decides to initiate insulin therapy. Can you identify the location in the body where insulin is produced?