Liver enzymes are the protein released by the liver in a continuous manner. However, sometimes due to various reasons, the liver starts to produce more than required concentrations of the liver enzyme. The high level of liver enzymes can cause mild to acute diseases in dogs. In severe cases, it can even cause death. A question that might come to your mind is; how long can that dog live with the high level of enzyme?

A moderately high level of liver enzymes is common in dogs. Dogs can bear a moderate-high level of the liver enzyme without showing clinical signs. However, in certain cases elevated levels of liver enzymes cause several diseases of the liver. But Dogs can live long with an elevated level of the liver enzyme without showing any sign of disease. And it largely depends upon the age, sex, breed, and immunity status of the dog.

The liver is one of the vital organs of the body, and it performs various functions. The liver produces many enzymes. The enzymes of the liver perform several different tasks. More than required production of liver enzymes compromises the normal functioning of the liver. To know more about the liver enzymes and their effects in dogs, continue reading till the end.

First, let’s discuss what are the normal functions of the liver, and liver enzymes? Then we will discuss, what are the effects of elevated liver enzymes?

Function of Liver and Liver Enzymes

The liver is one of the largest organs of the body and performs almost 500 different tasks. Major tasks of the liver include:


Detoxification is one of the vital functions of the liver. The liver removes all the harmful, toxic substances and chemicals from the body. Several types of toxins are present in the body; these toxins include residues of drugs, vaccines, environmental toxins, free radicals, and intestinal microbes. For detoxification, the liver releases several enzymes in the circulation. These enzymes convert the fat-soluble toxic or harmful products into water-soluble products. Then the water-soluble form of these toxic substances is removed through the liver.

Production of Substance

The liver produces various substances, like bile (bile helps in digestion), blood proteins, clotting factors, RBCs (RBCs recycle in the liver). Liver enzymes help the liver to carry out various functions that result in the production of several products.

Nutrients Breakdown and Absorption

With the help of various enzymes liver breaks down nutrients from the diet and makes them absorbable for the body tissue. The liver enzyme has a vital role in the breakdown as well as in the absorption of nutrients.


Liver is a storage organ. Most importantly the liver stores sugar and also regulates blood’s sugar level.

Hormone Regulation

Liver enzymes help the liver to regulate the hormonal function of the body.

Along these, the liver performs several other functions. Now let’s talk about some vital enzymes of the liver.

Basic Liver Enzymes in Dogs and their Functions

There are four vital liver enzymes in dogs: ALT (alanine Aminotransferase), GGT (Gamma-glutamyltransferase), AST (Aspartate Aminotransferase ), and ALP (Alkaline Phosphatase). Let’s have a look at each liver enzyme in detail to know more about its function.

Alanine Aminotransferase (ALT)

The vital function of the alanine aminotransferase is to convert alanine (amino acid) into pyruvate. Pyruvate is a crucial intermediate of cellular energy production. In healthy dogs, alanine aminotransferase concentration is low in the blood. In case of abnormality, the concentration of the ALT increases rapidly in the blood. A severe increase in ALT concentration can cause jaundice.

Gamma-glutamyltransferase (GGT)

Gamma-glutamyltransferase plays a significant role in detoxifying and metabolizing drugs and toxic substances. More than the required concentration of the GGT is due to liver injury or damage.

Aspartate Aminotransferase (AST)

Like ALT, AST also helps trigger different chemical reactions required for the normal function of the body. A low concentration of AST is present in the body and aids in carrying out several functions. However, a high level of AST starts to accumulate in the body in case of abnormalities, a high level of AST is widely due to liver injury.

Alkaline Phosphate (ALP)

Alkaline Phosphate helps break down proteins and convert them into different forms. The required amount of Alkaline Phosphate is variable. It largely depends upon the age, gender, blood type, and physiological status of the dog. If there is any problem with the liver or gallbladder the level of Alkaline Phosphate increases in the blood.

How do Liver Enzymes Increase in Dogs?

We have explained that the liver has excellent regenerative abilities. In most cases, liver damage becomes prevalent at the irreversible stage of liver damage. A moderate increase in the level of liver enzyme is not uncommon in dogs.

During a research, the sample was taken from 87 dogs. The research showed that 77% of the dogs had an increased alkaline phosphatase, and 48.3% had increased alanine aminotransferase (ALT) activities but 83.9% of the dogs didn’t show any abnormal clinical signs. This shows dogs with even a high liver enzymes can live a normal and long life.

However, a marked increase in the liver enzymes and their activity is an indication of liver disorder. And It is important to know the cause behind the elevated liver enzymes. So one can treat them as soon as possible. Three basic patterns elevate the level of liver enzymes in dogs.

  • Cholestatic
  • Hepatocellular leakage
  • Mixed

Let’s discuss the detail of all three patterns one by one:


Cholestatic is also called inducible enzymes. The enzymes include alkaline phosphatase (ALP) and Gamma-Glutamyl Transferase (GGT). The Predominant increases in the activities of the cholestatic or inducible enzymes occur due to a variety of conditions.

ALP activity is moderate In normal dogs. However, its activity is higher in growing dogs and also in dogs with the osteolytic disorder. The general increase in the inducible enzyme is widely due to endocrine disorders.

Increased concentration and activity of ALP and GGT are also due to hyperadrenocorticism, hyperthyroidism diabetes mellitus, altered bile flow, inflammatory bowel disease, cholangitis, cholecystitis, and biliary obstruction.

Sepsis and bile neoplasia can also cause an increase in the production and release of inducible enzymes. Exogenous substances also cause a marked increase in the concentration of GGT and ALP. Administration of Glucocorticoid and phenobarbital in dogs causes a moderate to a marked increase in serum GGT and ALP concentration.

Hepatocellular leakage

Aspartate aminotransferase (AST) and Alkaline Phosphate (ALP) are the hepatocellular leakage enzymes. Both enzymes are present in the cytosol of the hepatocytes.

Hepatocellular membrane disruption causes an increase in the production of ALT. The magnitude of ALT activity is directly related to the degree of hepatocyte damage. AST level also increased due to increased activity of creatine kinase (CK), and also due to primary muscle damage. A variety of hepatic and extrahepatic disorders can cause increased hepatocellular leakage enzyme activity.

Other than this, there are several reasons for the increase in ALT concentration, like Anemia, congestive heart failure, and shock. Dogs that undergo extraneous exercise may also face an increase in ALT concentration. An increased hepatocellular leakage enzyme activity also occurs due to hepatic abscesses and primary or metastatic neoplasia.

In general increased AST, activity is more sensitive than ALT activity for various types of liver damage. In other words, you can say an increase in concentration in AST causes more liver damage as compared to ALT.

Mixed Liver Enzyme Patterns

Concurrent increase of hepatocellular leakage and cholestatic enzyme activities suggests concurrent disorders. Hepatotoxins cause mixed liver enzyme patterns. However, Hepatotoxins also have the potential to induce inducible and hepatocellular enzyme leakage individually.

What are the Symptoms of the Elevated Liver Enzyme?

The signs and symptoms of elevated liver enzymes usually appear very late. Sometimes they appear in the late stage of the disease. Usually, veterinarians ask for the complete liver enzyme test in dogs diagnosed with hepatitis. The most common signs and symptoms of elevated liver enzymes are:

  • Jaundice (cause the whitening of the skin, whites of mucous membranes, and eyes caused by liver problems)
  • Dark urine
  • Pale-colored stools
  • Fatigue
  • Lethargy
  • Nausea and vomiting
  • weakness
  • Anorexia of mild to severe nature
  • Inflammation, Pain, or swelling in the abdomen
signs of liver disease in dogs

Along with the traditional sign and symptoms, an elevated level of liver enzyme is also expected in the dogs who:

  • Have a history of hepatitis or familiar liver disease
  • Are obese
  • Have a history of diabetes

What is the Best Test to Check Elevated Liver Enzymes in Dogs?

A veterinarian can perform several tests to evaluate the level of liver enzymes, but the most common of them is the chemistry panel. The chemistry panel evaluates the level of enzymes released by the liver. The test is an assessment to check the concentration of liver enzymes.

By seeing the concentration of enzymes, we can estimate the cause of the disease. For example, an increased level of ALT will indicate trauma, anaphylactic reaction, systemic illness such as thyroid disorders. While an elevated level of ALP may be an indication of bone cancer, and a high level of GGT is indicative of hepatitis and cirrhosis.

We have described that harmful elevated level of liver enzymes is variable among species. For example, a certain level of the liver enzyme might be abnormal for a dog and it might be causing diseases in the dog. But the same level might be safe or non-disease-causing for the other. But usually, the decision of the liver damage is made by seeing the percent increase in the liver enzyme.

Other than this, several other laboratory tests help to check the level of liver enzymes e.g., cytology and histology of liver tissue, ultrasound, and MRI.


An elevated level of liver enzyme activities is common in dogs and can also suggest several patterns of liver disease, including cholestasis, hepatocellular damage, or both. If we sum up the discussion, then it would not be wrong to say that dogs can bear a marked increase in liver enzymes. Dogs usually live long even with elevated liver enzymes, and death only occurs in older or in dogs that are dealing with two or more diseases simultaneously.