Insulinoma and diabetes cause the opposite results, both from problems with the pancreas. In untreated diabetes there winds up being too much sugar in the blood stream and insulin is given (and sugars if there winds up being too much insulin given which is what you were thinking of) whereas in insulinoma there start being tumors of a type which do not respond to the blood glucose levels and which constantly pump out large amounts of insulin. The common symptoms (from tiredness to fully out of it grande mal seizures to death) happen because the brain isn't getting enough sugar. There is a hypothesis that has some weight behind it (though it is still a hypothesis) that too much starch and sugar in the diet may lead to the formation of these growths. Also, removing them from the diet early on helps many ferrets (but not all) go longer with surgery or meds. It is important to see which works best for a given individual. In the last stages of insulinoma when the islet cell tumors have taken over much of the pancreas or suppressed much of it, or both then when meds no longer work at their highest levels adding sugars to the diet can sometimes give as long as a few extra good quality months. The meds used are Pred (usually Prednisolone because it skips the liver processing step needed by Prednisone so it is often more effective), and Diazoxide. When caught late it can be counted on to return. If caught early it returns in about 40% of the individuals within 10 months as per vet pathologist Dr. Bruce Williams. It almost never metastasizes to other organs (the hallmark of malignancy is the ability to show up in DISTANT organs). Blood sugar in ferrets can be dropped by other things as well, but much more rarely. Some examples include carcinoma (Been there once.), lymphoma (Been there once.), sepsis (Been there once.), inability to get enough nutrition due to a severe GI disease (Been there a few times.). Amazing what you encounter and learn in 23 years... No, never give insulin to a ferret with active insulinoma because there is already too much naturally produced insulin present. I suggest reading the write up at http://www.afip.org/ferrets/index.html Diabetes is much more rare and sometimes occurs temporarily after insulinoma surgery till the suppressed tissues become active again. That is usually very short term. On very rare occasions there are ferrets with permanent diabetes for whatever reason which is one reason if a ferret is out of it to test rather than just start meds. For diabetes info I suggest http://fhl.sonic-weasel.org (ALWAYS A GREAT PLACE FOR ALMOST ANY TYPE OF HEALTH INFO) For both also go to http://www.miamiferret.org Either can be fatal, but there are approaches to use which are exceedingly valuable. [Posted in FML issue 4572]