Hormonal Diseases in Ferrets

There are four major diseases caused by hormonal disturbances in ferrets:

• Adrenal gland disease
• Diabetes mellitus
• Insulinomas (insulin-producing tumors)
• Abnormally high levels of estrogen associated with persistent estrus in intact female ferrets

This handout discusses the first two diseases: adrenal gland disease and diabetes mellitus. These are two of the most common hormonal diseases in ferrets. The latter two diseases are covered in separate handouts.

What is adrenal gland disease? 

Adrenal glands are small glands located on each side of the abdomen in ferrets and positioned just in front of each kidney. In a diseased state, one or both adrenal glands are hyperactive. Adrenal gland disease is common in North American ferrets that are over three years of age. 

In dogs and cats, this condition is called hyperadrenocorticism or Cushing's disease, and it results from a pituitary gland tumor that produces a hormone that causes the adrenal glands to produce excessive amounts of a steroid called cortisol. In ferrets, however, true Cushing's disease does not occur. Hyperactive adrenal glands and adrenal gland tumors occur, but the diseased glands do not produce excessive cortisol levels. Instead, there is increased production of sex-related hormones like estradiol, androstenedione, and progesterone. 

What are the clinical signs of adrenal gland disease in ferrets? 

The most common initial sign of adrenal gland disease in ferrets is hair loss (alopecia) on the top of the pelvis, along the tail, and/or along the flanks. Pruritus (itchiness) is common with adrenal gland disease due to the hormone imbalance. 

Affected female ferrets often develop an enlarged vulva, while males with adrenal gland disease often have prostate gland enlargement, which puts pressure on the urinary tract and creates a mechanical blockage and inability to urinate. In this condition, a male ferret will show abdominal distension along with straining to urinate. This is an emergency condition that requires immediate veterinary treatment. 

How is adrenal gland disease diagnosed? 

An experienced veterinarian may be able to palpate (feel) the enlarged adrenal glands just in front of the kidneys. Abdominal ultrasound may be helpful in some cases, as it may help determine whether one or both adrenal glands are affected. Hair loss and a swollen vulva can sometimes confuse the diagnosis, as they are also common signs of persistent estrus, which is common in intact female ferrets. 

In many cases, clinical signs and a thorough medical history can lead to a presumptive diagnosis of adrenal gland disease. Many experienced exotic mammal veterinarians can presumptively diagnose the disease based on symptoms alone. The definitive way to diagnose adrenal gland disease is to send a blood test to a reference laboratory to measure adrenal gland hormone levels. 

How is adrenal gland disease treated? 

Adrenal gland disease may be managed surgically or medically, depending on many factors, such as which gland is affected, the size of the adrenal gland, the availability of an experienced surgeon, the age of the ferret, the severity of clinical signs, the overall health of the ferret, the presence of other diseases and sometimes financial considerations. Most cases are due to an increase in the size of the adrenal tissue or a benign adrenal tumor (adrenocortical adenoma). 

A more aggressive form of the disease is due to an adrenocortical adenocarcinoma. Injectable hormone therapy with leuprolide acetate or the use of an injectable deslorelin hormone implant will resolve symptoms in most ferrets with adrenal gland disease. Pruritis should subside quickly and hair should be back to normal 1 to 2 months after starting medical therapy. In the case of adrenocortical adenocarcinoma, however, medical therapy will generally fail to reverse symptoms. 

There is some information about using melatonin to treat ferrets with adrenal gland disease. However, veterinarians do not recommend this therapy because it merely provides a boost in hair production but does not help other symptoms or help shrink the diseased adrenal gland. Although unwise, some owners may choose not to treat the disease at all, especially if the ferret is senior or the clinical signs are mild. Before deciding about treatment, discuss the advantages and disadvantages with a veterinarian experienced in ferret diseases and surgery. 

What is diabetes mellitus? 

Diabetes mellitus, caused by inadequate production of insulin, is extremely rare in ferrets. It may occur secondary to the surgical removal of a pancreatic tumor (insulinoma), especially where numerous cancerous nodules are found in the pancreas and parts of the pancreas are removed to remove the cancerous portions.

A presumptive diagnosis of diabetes mellitus can be made based on persistently elevated glucose levels in the blood and urine, but a definitive diagnosis requires measurement of low blood insulin levels in the face of high blood glucose levels. A ferret with diabetes mellitus can be treated with daily insulin injections. As with monitoring diabetes in other species, the ferret's urine should be monitored daily for the presence of glucose. 

What about thyroid-related hormonal diseases?

Despite the prevalence of estrogen-related and insulin-related endocrine disorders, to date there are no reports of thyroid-related hormonal disease in ferrets.