Characterization of a lipoprotein lipase class III type defect in hypertriglyceridemic cats.

Lipoprotein lipase (LPL) is an important enzyme involved in triacylglycerol metabolism in plasma. We have characterized the deficiency in LPL activity in hypertriglyceridemic cats. Pre- and postheparin plasma contain a similar high level of LPL mass, which has no enzymatic activity. This indicates that the cats produce an abnormal LPL protein which is inactive and fails to bind to the endothelium. This phenomenon is similar to the Class III type defect characterized in human LPL deficiency. Molecular analyses indicate that there is no major structural rearrangement in the LPL gene, and that the mRNA and protein products are normal with respect to size and quantity. These cats present unique animal model for human LPL deficiency.