Two hormonal (endocrine) disorders, insulinomas and hyperadrenocorticism, are common in ferrets. Both are described in this section.
An insulinoma is a tumor found in the pancreas that overproduces insulin. These tumors are very common in ferrets older than 3 years of age. The elevated insulin levels result in low levels of blood sugar (hypoglycemia)—a condition that is the opposite of diabetes. Ferrets with insulinoma have signs such as weakness, lethargy, slight or partial paralysis of the rear legs, increased salivation, and teeth clenching or grinding. In severe cases, seizures may occur. A veterinarian will make a diagnosis based on whether or not the ferret shows signs of hypoglycemia along with corresponding normal or elevated insulin levels. This is done using a “fasting” glucose test. You will be asked to withhold food from the ferret for about 4 hours before the appointment; a blood sample will then be drawn during the visit. Other blood work is usually normal. Ultrasonography only occasionally reveals these tumors.
Medical and surgical treatments are possible, but there is no cure. Surgical treatment involves either cutting out the mass or removing the part of the pancreas where the tumor is located. Because the cancer is found throughout the pancreas, it is unlikely that surgery will remove the entire tumor. A period of normal blood sugar levels occurs following surgery in some cases, but most ferrets require continued medical treatment. The benefits of surgery include reducing the severity of signs, easing management, and moderately increasing survival time. However, this does not reduce the tumor directly. Medical treatment is lifelong, and does not reduce the tumor directly. Glucose levels should be monitored 5 to 7 days after changing doses and at least every 3 months afterwards.
If a ferret goes into a seizure—signs include twitching, shaking, and unresponsiveness—it is possible to lay the animal on its side and rub honey or corn syrup on its gums using a cotton swab to return it to normal behavior. Check with your veterinarian once you have done this to see about adjusting your ferret's medications.
Hyperadrenocorticism in ferrets is caused by overproduction of the sex hormones (that is, progesterone, testosterone, and estrogen) by a portion of the adrenal gland. It can be seen in ferrets as young as 1.5 years old. Having your ferret spayed will help prevent this disease. The most common sign is hair loss beginning on the tail and rump and progressing up the body towards the head. In females, a swollen vulva and enlarged nipples may also be seen, while males may become aggressive and have difficulty urinating due to an enlarged prostate gland. Bone marrow suppression may follow severe elevation of estrogen levels in the blood. Ferrets with these signs should be taken to a veterinarian as soon as possible.
A veterinarian will make a preliminary diagnosis based on the history and physical examination of the ferret. The enlarged adrenal glands may be felt in front of the kidneys. Routine blood tests are usually normal. Ultrasonography may show enlarged gland(s), but your veterinarian needs to measure the sex hormones to make an accurate diagnosis.
Treatment for this condition includes medical and surgical options. Surgical removal of the adrenal gland(s) is more likely to cure the disease than medical management, but the disease will return in about half of all affected ferrets. If both sides are affected, a partial removal of the adrenal glands can be performed.
An examination of gland tissue may reveal that the disease has progressed to 1 of 3 levels: hyperplasia, adenoma, or adenocarcinoma. Functionally all 3 grades are similar, and the spread of cancer cells outside the glands is unlikely. Because the adrenal glands produce other hormones needed by the body, ferrets that have both adrenal glands completely or partially removed may develop other problems due to a lack of those hormones. This condition can be treated with supplements.
Signs can be reduced through medical management, but such treatment does not affect the adrenal gland, and the tumor may continue to enlarge. It is important to understand that this is a lifelong treatment to control the signs of the disease. Ferrets should be closely monitored if longterm medical treatment is used. Melatonin can be used to treat hair loss and may help with other signs as well. Other drugs used to control sex hormone levels in humans are beginning to be used in ferrets and show promise in controlling the signs.
Last full review/revision July 2011 by James K. Morrisey, DVM, DABVP (Avian)