Cushing’s occurs in dogs who are producing excessive amounts of cortisol, an important hormone that helps to regulate the body’s metabolism.
Cortisol plays a vital role in protein, carbohydrate and fat metabolism and is released into the bloodstream at times of stress to prepare the body for a flight or fight response.
Cortisol is produced by the adrenal glands - two small glands located in the abdomen, next to each kidney. A hormone called ACTH controls the production and release of cortisol from the adrenal glands. ACTH itself is produced by the pituitary gland, a pea-sized gland located at the base of the brain.
The concentration of cortisol in the blood of healthy animals varies greatly as the body’s demand for cortisol fluctuates. For example, during a period of anxiety or illness, it is normal for the adrenal glands to increase their production of cortisol. Once this period of stress has passed, the cortisol concentration in the blood returns back to normal.
In dogs with Cushing’s syndrome, there is a chronic overproduction of cortisol over weeks and months. Although the concentration of cortisol in the blood of a dog with Cushing’s also fluctuates greatly, it tends to be, on average, much higher than in healthy dogs. The excessive amount of cortisol released into the bloodstream has a harmful effect on the function of many organs and the body’s metabolism.