Glucose Metabolism in Healthy Dogs

To understand the disorder of diabetes in dogs, we must first look at how insulin and glucose interact within a healthy dog and the importance of that interplay. Glucose is a kind of sugar molecule that is used throughout the body as a primary source of fuel for the millions of cells that make up your dog’s tissues and organs. The glucose in your dog’s bloodstream originates in its food, particularly in the carbohydrates present in many dog food formulations. As the dog digests its meal, glucose is absorbed through its intestinal lining into the bloodstream, where it is transported for consumption throughout the body.

Though your dog’s cells readily consume glucose for energy, they are unable to do so without additional help from another molecule, called insulin. Insulin enables cells to transport glucose across their membrane where it can be put to good use as a source of energy for the various cellular functions of that cell. To use a metaphor, if you imagine a cell as an automobile and glucose as gasoline, insulin is the key that unlocks the gas tank.

By controlling the uptake of glucose, a dog’s body can regulate blood sugar levels within a healthy range. However, as you might imagine, being unable to reliably do so can cause some very serious and systemic issues for your furry friend.

Glucose Metabolism in Diabetic Dogs

The digestion and metabolism of glucose may sound simple in principle, but the process is quite delicate and vulnerable to disruption. In fact, there are two main ways in which the healthy regulation of blood glucose can be interfered with:

Insufficient insulin production (Type 1)

A healthy dog will secrete insulin from an organ called the pancreas. This simple structure is located near the stomach, and plays a crucial role in digestion. A number of enzymes and digestive juices are produced within the pancreas and released into the digestive tract to aid in the breakdown of the different fats, proteins, and carbohydrates your dog consumes. The pancreas also plays a second role of producing hormones and excreting them into the bloodstream to regulate the downstream products of digestion. This is where is normally produced and released in response to the pancreas’ detection of elevated blood sugar levels (usually following a meal).

Some unfortunate dogs have an immunological condition whereby their immune systems mistakenly consider the pancreatic beta cells (the specific cells responsible for insulin excretion) to be foreign bodies. As a result, they target these cells for destruction, wiping out the dog’s insulin producing capacity altogether. When the resulting insulin deficiency leads to diabetes, this is known as type 1 diabetes, and is the same mechanism that causes type 1 diabetes in humans. Type 1 diabetes is thought to be inherited and is not thought to be triggered or caused by lifestyle factors, unlike the second form of the illness.

Insufficient insulin responsivity (Type 2)

Not every dog with diabetes is incapable of producing insulin. In order for insulin to perform its function effectively, it must not only be present in the bloodstream, but the cells of the body must be capable of responding to it appropriately. Some dogs can develop a resistance to the effects of insulin, which limits the ability of their cells to import glucose from the bloodstream as fuel.

As with type 1 diabetes, insulin-resistant diabetes (or type 2) is common to humans and dogs. In both species, the disease is thought to be acquired over time, typically due to lifestyle factors that lead the body to become desensitized to the presence of insulin.

While these two categories of diabetes span most cases, there may be other situations or reasons why a dog may experience diabetes. For example, gestational diabetes can occur temporarily in female dogs during or around the time of their pregnancy. If your dog is expecting a litter of puppies and you notice some of the symptoms discussed in this article, gestational diabetes may be the culprit.

Effects of Diabetes

Regardless of the underlying cause, the effects of all forms of diabetes are similar in many ways, including their potential severity. Limiting the production or efficacy of insulin can lead to two main harmful consequences for a dog, namely, the starvation of their cells, and the accumulation of excessive glucose in their blood.

There are a host of potential symptoms and complications that may occur as a result of diabetes. Most of these stem from one or both of these underlying causes in some way. Understanding how diabetes can affect a dog can therefore help diagnose and treat their illness more effectively, meaning that pet owners should stay informed and vigilant about their pets’ health.

Recognizing Diabetes in your Dog

Early signs and symptoms

Untreated diabetes is a progressive illness, which means that it becomes more severe over time. Modern medical interventions are quite successful at preventing the progression of many complications of diabetes, but reversing existing damage is always a much more difficult task. Beginning treatment as early as possible in the course of the progression of the illness is therefore extremely important, but can also be challenging.

Diabetes in humans can be notoriously difficult to detect early on because of the mild nature of its early symptoms. The challenge is made even more difficult in canine patients because of their inability to communicate their subjective experiences to the people around them. Thus, diabetes can only be detected through external observation by someone who knows a particular dog and their normal behavioral patterns well. Noticing changes in a dog’s behavior can be a red flag for owners that the dog may not be feeling like their usual self and may warrant further investigation on the owners’ part.

Two classic symptoms of diabetes are excessive urination and thirst. These symptoms go hand in hand often, as they share a common root cause. The presence of extremely high levels of blood sugar, as in an untreated diabetic dog, can cause the kidneys to attempt to restore normalcy by passing the glucose through the dog’s urine. In turn, constant and excessive urination will dehydrate a dog, leaving them parched and seemingly endlessly thirsty.

Fortunately, this is an easy symptom to detect, even in less attentive owners. Most dogs need their owners to let them out to urinate, so it should become apparent if your dog is whining at the door to go out more often than they normally would. And, if their water bowl seems to always be empty, or they resort to a toilet bowl despite having been given water recently, this may also become readily apparent.

A potential consequence of cellular starvation, the other primary mechanism of harm caused by diabetes, is rapid and unexplained weight loss. When cells cannot access the energy that they require to function, the tissues of the body can become degraded and atrophied. This loss of bulk can cause dogs to thin out and become noticeably lean. In response, the dog may consume more food in the hopes of gaining sufficient energy. This can lead to a paradoxical situation where the dog seems to be ravenously hungry but simply cannot keep their normal weight.

Advanced signs and symptoms

As diabetes progresses, many of the symptoms simply become more pronounced and harder to miss. Still, other symptoms are only likely to appear once your dog’s diabetes has been left untreated for some time. Some very hard-to-miss examples would include blindness or seizures. Less noticeable but more severe are symptoms like kidney failure, which can be fatal.

Again, the key to avoiding these complications is to pre-empt them with effective care. It’s best to err on the side of caution if you think your dog might be acting strangely, or if any new behaviors seem to be getting worse.

Risk Factors

While every pet owner should be attentive to their animals’ well-being, some dogs may be predisposed to diabetes due to having more risk factors, and may thus warrant more careful monitoring. Some risk factors known to increase the likelihood of diabetes in dogs include the following:

  • Obesity: Dogs who are heavier than is healthy for their size are more likely to develop pancreatitis and diabetes. If your vet has indicated your dog is overweight, they may be more at risk for diabetes.
  • Genetic pre-disposition: Some evidence suggests that diabetes may be more prevalent in certain breeds. Certain breeds of terrier, many popular “toy” dog breeds, and some larger breeds like Poodles and Samoyeds, can experience a greater risk.
  • Age: As dogs become more senior, they become more likely to acquire health issues like diabetes. Once your dog reaches middle age, it may be prudent to keep an eye out for any changes in their behavior.
  • Sex: Female dogs are more likely to become diabetic than male dogs, with unspayed females occupying the highest-risk position.

Diagnosing Your Dog

Signs and symptoms are good indicators that something is amiss with your dog’s health, but there’s no substitute for a clinical diagnosis made by a veterinary professional. It’s important that you bring your pup to the vet to have them assessed if you think they may be experiencing a health condition, including diabetes.

Once there, the vet may use several techniques to confirm or rule out diabetes. These could include a physical examination, a questionnaire for the owners about changes in the dog’s behavior, as well as sampling the dog’s blood and urine to assess their sugar contents. Using all this information, a vet should be able to determine if diabetes is a factor in whichever symptoms you’ve been noticing.

Veterinarian checking dog

Treatment and Monitoring

Dogs are not called man’s best friend for no reason; people love their dogs, and the prospect of them becoming ill with a chronic disease can be very worrying. Fortunately, with effective treatment, your dog may be relatively unaffected by their condition and can expect to continue living a happy and healthy life.

Treating canine diabetes does involve a higher level of care than most dogs demand. Owners will need to incorporate new routines as part of caring for their dogs, which may include monitoring glucose and administering insulin. Typically, insulin is administered with a needle once per day, while glucose monitoring schedules can vary wildly. Be sure to consult with your vet about which medications and monitoring strategies to use and how often.

Beyond pharmacological treatments, diabetic dogs can benefit from lifestyle modifications, such as adding more exercise and activity into their daily routine. Keeping active is an incredibly important aspect of regulating blood sugar and keeping a healthy body weight and should not be overlooked. Fortunately, most dogs love to play by nature, so it shouldn’t be too difficult to find activities that you and your dog can enjoy together, like playing catch or going for a scenic walk around town.

Samoyed Dog Running


Nobody likes to imagine their pets becoming ill, but humans are far from being the only ones vulnerable to common illnesses like diabetes. An important element of responsible pet ownership is therefore to stay informed about some of the more likely health complications your dog might experience so that you can respond quickly and effectively.

When it comes to diabetes in dogs, quickly spotting early signs can make a huge difference in the quality of your dog’s life thereafter. Dogs are creatures of habit, which makes spotting potentially relevant behavioral changes both easy and important. Picking up on subtle shifts in your dog’s daily habits may make all the difference in accessing potentially lifesaving care.