INVESTIGATIONS INTO HYPERLIPIDEMIA AND ITS POSSIBLE ...

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enzyme is to transfer triglycerides from LDL, VLDL, and chylomicrons to HDL 2 in
exchange for cholesteryl esters. This results in the production of cholesteryl ester-rich
LDL and triglyceride-rich HDL 2 molecules. 31,32,37,39,40 Due to the absence of this enzyme
in dogs, HDL 2 molecules continuously acquire cholesteryl esters, resulting in the
formation of HDL 1 molecules, which are unique to dogs. Cholesteryl esters are
transferred from various tissues to the liver for disposal or reuse through HDL 1 , rather
than through LDL or VLDL molecules, which transfer cholesterol to peripheral
tissues. 31,32,37 Thus, it is this function of HDL 1 that accounts for the lower incidence of
atherosclerotic disorders in dogs compared to humans. 31
Hyperlipidemia in dogs
Postprandial hyperlipidemia is physiologic and typically resolves within 7-12
hours after a meal, depending on the fat content of the meal. 14,31,37,49 Therefore, any
determination of serum lipid concentrations should always follow a fast of at least 12
hours. Persistent fasting hyperlipidemia is abnormal and can be either primary or
secondary to other diseases or drug administration.
Secondary causes of hyperlipidemia
Secondary hyperlipidemia is the most common pathologic form of
hyperlipidemia in dogs. 50 Several diseases have been reported to cause hyperlipidemia.