Adrenal gland disease is relatively rare in rabbits. Rabbits have two adrenal glands, situated near the kidneys within the abdomen.

Adrenal gland anatomy © David Perpiñán

The adrenal glands play an important role within the endocrine system and secrete hormones which are responsible for regulating blood volume, blood pressure and vascular tone, and are essential to keep the rabbit alive. The adrenal glands also normally produce low levels of sex hormones. Within each adrenal gland is an outer area (outer cortex) and inner area (inner medulla). These two sections differ in their function.

The main type of adrenal disease seen in other domestic pets (known as Cushing’s disease) has not been reported in rabbits. However, in neutered rabbits, the adrenal glands can occasionally develop disease that causes them to produce high levels of sex hormones, such as testosterone. This disease is associated with the production in the brain of elevated levels of the hormone, gonadotrophin-releasing hormone (GnRH), which in turn leads to increased levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH normally act on the reproductive organs, but in a neutered rabbit they stimulate the adrenal glands, causing them to produce increased levels of sex-hormones and other steroid hormones. This abnormal stimulation can lead the adrenal gland to develop a tumor (neoplasia).

Although rare, adrenal disease should be considered in rabbits displaying signs which may be indicative of the condition. These include:

• Persistent sexual behavior in neutered rabbits (mounting, chasing, biting, increased aggression and urine spraying).
• Reduced appetite.
• Enlarged clitoris in females.
• Muscle loss.

Adrenal disease can occur in both neutered male and neutered female rabbits, with males being more commonly affected. Any breed may be affected, with an average age of around 7 and a half years being the most common age at which rabbits present signs.

If your rabbit is displaying signs which may be caused by adrenal gland disease, you need to book an appointment to see your veterinarian as soon as possible. Your veterinarian will perform a clinical examination, as well as take a history from yourself. Cases of suspected adrenal gland disease can be confirmed by taking a blood sample from your rabbit to look at the hormone levels. There are reference ranges available for both neutered male and neutered female rabbits, so your veterinarian will be able to determine if your rabbit’s levels are abnormally high.

It may be possible to manage your rabbit with medication, but not all cases will be suitable for this, and in some cases it will not be successful. Your veterinarian may recommend surgical removal of the adrenal gland (adrenalectomy), which is the best option to remove the abnormal gland permanently. This is not a routine procedure in rabbits and your rabbit may require referral to an exotic specialist veterinarian or specialist soft tissue surgeon. Surgery may be curative, but clinical signs can reappear after surgery. For example, if only one gland is removed, the other one may still become affected.