>????????utomatic part of the stress response is to dump glucose into the blood stream.  This gives your body the extra energy it needs to fight or to run away.  Glucose needs insulin to release the energy locked inside it.  This creates an increased demand on the pancrease to produce more insulin.

So, if a person is in a constant state of stress, they can wear out their pancreas and become diabetic.

Stress can also make diabetes worse.  My husband is a type 2 diabetic and I have noticed that when he is under stress that his diabetes gets worse.