There are two types of diabetes in pets. In type I, more common in dogs, the pancreas simply does not produce insulin anymore. In type II, more common in overweight people and in heavy cats, the insulin is produced, but it isn't as effective as it should be. Insulin is a hormone that moves sugar from the blood stream into the cells. The cells need this energy from sugar, and if they cannot get it, they will try to get energy elsewhere by breaking down fat and muscle. Thus, animals with diabetes lose weight, sometimes suddenly and sometimes over a very long period of time. Since the sugar isn't being moved out of the blood stream, the animal's blood sugar measures very high. Over time this high level of sugar in the blood can lead to kidney disease in dogs and cats, cataracts in dogs and to neurologic problems in cats (ie, they walk funny).

Pets with diabetes will drink a lot of water and urinate a lot. This is due to an osmotic effect as sugar spills over into the urine water follows and the pet makes a lot of urine. As he pees a lot more, he gets thirsty, so he drinks a lot to compensate. As I mentioned before, they will also lose weight. This is in spite of a very good appetite, because the cells are literally starving for sugar, so they send messages to the brain to tell the animal to eat, even though his blood sugar may be through the roof. Other symptoms, like cataracts and extreme weakness come later in the disease.

Your veterinarian will readily suspect diabetes when there is a high blood sugar accompanied by sugar in the urine. However, final confirmation requires demonstrating persistent high blood sugars and in cats, we often have to run other tests to be sure.

The bad news is that we cannot cure diabetes. The good news is that we can treat it rather successfully. The even better news is that, with diet changes and insulin therapy, some cats will actually revert back to normal. So, how do we treat this disease?

Well, with insulin of course. Unfortunately, we do not have the ability to rig a pet up with an insulin pump that measures blood sugars and simply doses the appropriate amount of insulin throughout the day.

We have to treat pets more the old-fashioned way with twice a day insulin injections.. We also have problems with insulin preparations because most insulin is now made using the human genetic sequence. It used to be that insulin was prepared from pig or cow insulin, and our pets respond better to these, as the genetic sequence is more similar to a dog or cat. For a short time a company made Vetsulin, which was closer to the canine genetic sequence, but it is slowly being pulled off the market right now and animals are having to switch to the human insulin preparations. There is a brand new insulin called ProZinc that is a human recombinant PZI insulin manufactured by Boehringer Ingelheim. It is now available for pets and we'll have to see how they are responding to it. It may prove to be better in cats than in dogs.

Whichever insulin your veterinarian chooses is a good place to start. If it doesn't work for your pet, you can always try another preparation. You then have to learn how to give injections of insulin twice a day and you have to commit to this. You cannot skip a dose or meal. This might sound like a big deal, but it really isn't and most families can adjust to the new schedule.

(Dr. Katherine A. Saenger, DVM, owns Bees Ferry Veterinary Hospital and Boarding Kennel (www.beesferry.com) and is a former board member of the Charleston Animal Society (formerly John Ancrum SPCA.) If you have questions about pet behavior or health, or suggestions for column topics, e-mail her at vetsaenger@bellsouth.net.

and watch the column in coming weeks for her responses. )