Diabetes mellitus is one of the many diseases that affects both cats and humans. DM is generally considered a chronic endocrine (hormonal) disorder, though its duration can vary. It occurs in all ages and breeds, but primarily affects middle-aged to older cats, and more males than females.

The basic cause is loss of insulin, an indispensable hormone released from beta cells in the pancreas. A hormone is a substance released from one area in the body that travels in the bloodstream to exert its influence on other body tissues and organs. Because of its many functions, insulin has a direct or indirect effect on every tissue and organ in the body.

Insulin's primary role is to control glucose (sugar) transport and uptake by the body's cells. This glucose uptake provides the fuel for cell function and metabolism. Without proper nutrition, the cells and tissues are unable to do their jobs and must find alternate, less efficient energy sources.

Basically, insulin is involved in the body's use of all possible energy sources.