Insulinomas are tumors within the pancreas that produce excess insulin and are one of the most common neoplastic diseases affecting ferrets. Synonyms include functional islet cell tumor and pancreatic beta cell tumor. In the normal ferret, as in other mammals (including humans), the beta cells in the pancreas are responsible for producing a hormone known as insulin. Insulin is responsible for keeping the body's sugar (glucose) levels in balance. Most of us are familiar with diabetes; where not enough insulin is produced and the diabetic patient has a very high blood glucose level. Well, think of insulinoma as the opposite of diabetes - excess insulin produced by tumor cells in the pancreas results in a low blood sugar (hypoglycemia).

This ferret is very weak and lethargic because of a very low blood sugar (hypoglycemia) which can be caused by an insulinoma, also known as a B cell tumor. This is where tumor cells in the prancreas over produce insulin causing the blood sugar to plummet. Think of it as the opposite of diabetes

Insulinoma affects ferrets between the ages of 2 and 3 years, but is most commonly diagnosed in ferrets 4 to 5 years of age. The severity of clinical signs shown by the affected ferret varies with how fast these tumors develop and how long they have been present. Some ferrets develop a sudden onset of severe hypoglycemia, and the resulting low blood sugar causes the ferret to collapse into a weakened non-responsive state. In other ferrets, the onset of hypoglycemia is more gradual and the ferret will demonstrate intermittent signs of disease varying from periodic inactivity, depression and rear limb in-coordination to hypersalivation and pawing at the mouth. If the blood sugar drops very rapidly, the ferret with insulinoma may have tremors, seizures or go into a coma due to lack of glucose in the brain.

Diagnosis of insulinoma is usually made by associating the above clinical signs with a low blood glucose that can be measured by your veterinarian. Most veterinarians agree that a fasting blood glucose level less than 70mg/dl is very suggestive of insulinoma. Your veterinarian will want to rule out other causes of hypoglycemia which include; anorexia/starvation, severe bacterial infection and liver disease. A measurement of the ferret's serum insulin level may also be recommended to help with the diagnosis.

If the ferret is showing signs of severe hypoglycemia (weakness,collapse) owners can rub honey or corn syrup onto the gums. Once the ferret has improved, feed some of its regular diet and schedule an appointment with your veterinarian. Long-term treatment recommendations for insulinoma include surgery, medical therapy and dietary modification. The choice of therapy depends on severity of clinical signs, the age and overall health of the ferret and owner preference. Medical therapy involves the daily administration of drugs that will help the body produce more glucose and use it more efficiently. Most veterinarians start with twice daily prednisone and adjust the dose in response to the ferret's blood glucose levels, as well as how the ferret is doing clinically. If control is poor another medication, diazoxide (Proglycem), can be added to the regimen. In addition, ferrets with insulinoma should be fed many small meals throughout the day. A diet containing high quality protein and moderate levels of fat is preferred. Food with processed sugar or high levels of simple carbohydrates (such as fruit, semi moist cat food, cookies, etc.) should be avoided.

Keep in mind that regardless of which treatment option is chosen, ferrets with insulinoma are not cured, but rather controlled, and that blood glucose concentrations will need to be checked periodically. When treatment regimens are followed, many ferrets will continue with a good quality of life for one or more years.