Here's why:

* Endocrinology is the study of hormones, the chemical messengers produced by the body.

* Diabetes is a metabolic disorder characterized by high blood sugar levels.

* Insulin is a hormone produced by the pancreas that regulates blood sugar levels.

* Diabetes can be caused by either insufficient insulin production (type 1 diabetes) or the body's inability to properly use insulin (type 2 diabetes).

Therefore, because diabetes is a disorder of hormone regulation, it falls under the purview of endocrinology.