The kidney is traditionally considered an exocrine gland. This is because it produces urine, which is an external secretion that helps regulate bodily fluid volumes, composition, and eliminates nitrogenous waste products. However, the kidney also plays a role in hormone production, which is a characteristic of endocrine glands. These hormones have both local and systemic effects on the body.
Therefore, the kidney can be categorized as both an exocrine and an endocrine gland.
