The following article may be reprinted by anyone desiring to disseminate this information in a newsletter or non-commercial publication. This material may not be altered or changed in any way. Under Title 17 of the U.S. Code, Section 105, copyright protection is not available for any work of the United States Government. Islet Cell Tumor in the Ferret Islet cell tumors, also known as insulinomas, are the most common neoplasm in the ferret, based on the frequency of surgical and autopsy submissions at the Armed Forces Institute of Pathology. Over a period of two and a half years, this neoplasm alone has accounted for almost 15% of all ferret submissions. Islet cell tumors derive their name from their cell of origin. These neoplasms arise in the "islets of Langerhans" - a group of special cells in the pancreas which produce insulin (also giving rise to the term insulinoma). Insulin is a hormone which allows most of the cells in the body to utilize the glucose in the blood. The excess levels of insulin produced by these tumors drive the glucose in the blood into the cells of the body, causing a dangerously low blood glucose level, known as hypoglycemia. (In diabetes, the opposite is true - low levels of insulin production render the animal's cells unable to use glucose, and dangerous hyperglycemia results). Not all islet cell tumors appear to be functional, however. Islet cell tumors are often found as incidental findings at autopsy of animals dying of unrelated causes. Finally, a small percentage of animals fail to show characteristic signs of hypoglycemia, or show signs that are so subtle that they are not noticed by the owner and picked up on routine blood screening for other conditions. Hypoglycemic ferrets may exhibit a wide range of clinical signs. Weight loss appears to be a common finding in affected animals, and is occasionally the only sign. This is an excellent reason why you should periodically weigh your pet as part of a good preventive health program. Signs that are more diagnostic of islet cell tumors are episodic depression and lethargy, which in some animals manifests as stupor (apparent loss of touch with its surroundings), salivation, difficulty in using the hindlegs, vocalization, and in cases of severe hypoglycemia, seizures. Diagnosis of islet cell tumors is fairly simple and consists primarily of measuring the blood glucose levels in the ferret, which your vet can do if you suspected this problem. (Some vets additionally measure insulin levels, but in most cases, this is unnecessary and wastes valuable time.) Animals with blood glucose levels less than 60 mg/dl should be strongly suspect of having one or more of these tumors. Exploratory surgery in hypoglycemic but otherwise healthy ferrets should be scheduled at the earliest possible time. In animals where surgery is not an option, or until such a time as surgery is possible, medical management may be attempted by using a combination of prednisone (which raises blood glucose levels by mobilizing carbohydrate stores) and diazoxide (Proglycemr) an antihypertensive drug which appears to decrease islet cell secretion of insulin. It is important to realize that this is only a temporary measure and rarely is effective in controlling the animal's hypoglycemia for a long period.. It is also important to note that in a large number of cases (5/6 in one study), ferrets that had islet cell tumors surgically removed developed a second or more tumors at a later date. (Additionally, make sure that your veterinarian, if surgery is performed, takes a moment to check the adrenal glands for those extremely common proliferative lesions we so often see in ferrets.) If you have a several ferrets, it is extremely likely that one of them, sometime during its life, will develop an islet cell tumor; it's the "nature of the beast". Just watch them closely for the clinical signs that I have described, and have your vet check them if you have even the slightest indication of a problem. Happy ferreting!!! Bruce Williams, DVM [log in to unmask] 1. Marini, RP et al. Functional islet cell tumr in six ferrets. JAVMA 202(3) 430-432, 1993. 2. Kawasaki, TA Personal communication. [Posted in FML issue 0635]