Canine Liver Enzymes

" Canine liver enzymes are used to measure the health of a dog liver and as an indication of specific dog illnesses. The liver is one of the vital organs in the body. Different physiological mechanisms, such as metabolism, storage of glucose, blood cell functioning and even filtering and removal of waste are associated with the liver. This organ contains different primary and secondary liver enzymes which help in the speeding-up and in maintaining the regularity of all functions. Common types of dog liver enzymes are Alkaline Aminotransferase (ALT), Alkaline Phosphatase (ALP), Isoenzymes and Gamma Glutamyl and Transpeptidase (GGT). Canine elevated liver enzymes are observed as a sign of several different diseases, such as in Cushing’s disease, pancreatitis, hepatitis, metabolic disorders, side effects to drugs, poisoning and in some congenital (inherited) disorders. Dog elevated liver enzymes can be detected by using serological laboratory tests. Sometimes, a few recurring symptoms can be associated with higher liver enzyme levels. However, they cannot be termed as specifically indicating this problem. Treating any underlying cause and the specific condition can resolve elevated liver enzymes, but it usually takes a long time due to a delayed excretory push which means since the liver is working at a reduced level, it takes longer for it to work its way back to normal levels.."

Types of Canine Liver Enzymes and Elevated Dog Liver Enzymes:

Canine liver enzymes are proteins which increase the rate of chemical reaction in the liver. Therefore, sometimes they are also called biological catalysts. In the liver, different enzymes hasten the hepatic (liver function) activity and support functions. AminoTransferase (ALT), Alkaline Phophatase (ALP), Isoenzymes and Gamma Glutamyl Transpeptidase (GGT) are some common dog liver enzymes.

The following is a brief overview of each enzyme and the conditions associated with elevated levels:

• AminoTransferase (ALT): This is most specific liver enzyme in dogs. Elevation of this enzyme usually is noticed in the intracellular fluids of the body, and is commonly observed if hepatic necrosis (liver cell death)occurs, especially in cases that are acute (sudden) and severe in nature. ALT levels can elevate up to three times normal. Higher levels are possible in the case of some non-hepatic diseases, such as in inflammation of gastrointestinal tract, cardiac collapse and anemia.
• Alkaline Phosphatase (ALP): This enzyme is usually specific to the bile duct of the liver. It can be elevated in cases where the bile duct is blocked or congested for any reason, either external or internal to hepatic malfunctioning. This type of canine liver enzyme diffuses into serum with liver enzyme elevation noted during laboratory testing.
• Isoenzymes: Isoenzymes are proteins which chemically resemble Alkaline Phospatase (ALP). ALP is found in other organs of the body such as the kidney, intestine and placenta. Elevation of these types of enzymes found elsewhere in the body should be differentiated from ALP found in the liver. Elevated levels are usually noted in canine adrenocorticism, or during prolonged use of glucocorticoids in dogs.
• Gamma Glutamyl Transpeptidase (GGT); GGT is another type of canine liver enzyme, which is elevated either in cases of cholestasis (Bile Duct Blockage), hyperadrenocorticism, prolonged use of glucocorticoids. Unlike ALP, the level of this enzyme is usually not elevated in young growing dogs.
• Other Serum Proteins: There are some proteins, which are either produced in the liver (but does not work primarily as part of the liver) or they are produced in organs that are associated with the liver. These may act as enzymes. Serum Albumins, Serum Globulins, Bilurobin are some examples. Slight or severe elevation can be noticed in hepatic diseases and dog renal (kidney) diseases.

Diseases Associated with Canine Elevated Liver Enzymes:

Canine liver enzymes are correlated with the causes of various diseases, i.e. elevation is either a result of hepatic (liver) diseases or some hepatic diseases are primarily caused by elevation of dog liver enzymes. In either condition, it should be noted that laboratory confirmation of the elevated levels helps in forming a definitive diagnosis, and thus treatment is made possible.

The following are some common diseases which are directly related to canine liver enzymes which are elevated:

• Jaundice: Jaundice is actually a symptom of a hepatic problem, which occurs due to the inability of the liver to remove bilirubin. Thus level of bilirubin become elevated in a dogs cellular contents.
• Pancreatitis: Due to pancreatitis, the blockage of the dog bile duct becomes more frequent. The level of the liver GGT enzyme rises, thus it accumulates within the pancreas and the kidney, thus causing complications.
• Hepatitis: Inflammation of the liver occurs in cases of infectious hepatitis. Cells are invaded by bacterial, viral or parasitic agents. Due to cellular destruction and abnormalities, the number of enzymatic cells increases, with elevated dog liver enzymes of this type noted in body fluids.
• Metabolic Disorder: Obesity, diabetes and dog fatty liver disease are some metabolic disorders, where the elevation of liver enzymes is possible.
• Cushing’s Disease: In Cushing’s disease, adrenal hormones are released in excess, thus the elevation of liver enzymes is most probable for the reason that the production of these enzymes is controlled by these hormones.
• Miscellaneous: Some congenital canine liver problems such as congestive failure of the heart and kidneys and use of some drugs in excess, such as anticonvulsant drugs and corticosteroids can also result in canine elevated liver enzymes.

Treatment of Canine Elevated Liver Enzymes:

Treatment of canine liver enzyme levels that elevated are usually defendant upon the diagnostic results, i.e. severity and level of elevation. The primary cause should be identified and treated. Diseases which cause elevation of an enzyme level should be treated specifically . Monitoring tests should be conducted at least once in a week during treatment.

Dog food should be replaced by reducing fats, proteins and salt content in the dog's diet, especially table salt. Canine elevated liver enzymes are not a simple condition, thus it should only be attended to by a veterinarian. Complications may lead to incurable forms of disease, thus should be treated in during the initial stages only.

Some homeopathic products that target liver function may be a helpful to both  restore and keep dog liver enzymes at normal levels. There are three types of natural dog liver support products available: 

• Overall Canine Liver Support: These products are formulated for general liver support. Products such as Liver-Aid Formula can be used both during treatment and for additional support after treatment.
• Canine Adrenal Gland Liver Enzyme Support: Products such as Cushex are  formulated for dogs that are experiencing an abnormality in the adrenal gland. 
• Removal of Dog Enzymes: Another product, DetoxPlus, is formulated to support the  removal of additional enzymes and is only for support after recovery.

Check with your veterinarian on the use of any therapy.  

Treatment of elevated liver enzymes in dogs requires an approach that recognizes that the liver is not functioning properly. Before treatment,  the level of secretions from the liver are significantly reduced, which in turn slows down digestion.  When medications and dietary change is introduced, treatment can take a long period of time, since the reduced levels of digestive activity causes a delay in treatment absorption into the body. There is also a delay in the excretion of drugs after complete absorption.  After some time, liver function will work its way back to normal.

References:

The Merck Veterinary Manual

Leslie Ernest, Veterinary Endocrinology; Reproduction (Lea & Febiger, 2003)

Washington State University College of Veterinary Medicine