Evaluating the influence of hepatic triglyceride and lipoprotein lipases on lipase assays used to diagnose pancreatitis in dogs and cats.

Abstract

BACKGROUND: Pancreas-specific lipase and lipase activity measured by immunological assays (Spec cPL and Spec fPL) and colorimetric assays (1,2-o-dilauryl-rac-glycelo-3-glutaric acid-(6'-methylresorufin) ester [DGGR] and triolein), respectively, are used to diagnose pancreatitis in both dogs and cats. However, DGGR and triolein assays may be influenced by extrapancreatic lipases, including hepatic triglyceride lipase (HTGL) and lipoprotein lipase (LPL). OBJECTIVES: To investigate the effect of extrapancreatic lipases on immunological and colorimetric assays by measuring changes in HTGL and LPL activity following heparin administration. METHODS: Six healthy Beagles and six adult purpose-bred cats were enrolled. HTGL and LPL activities were induced by intravenous heparin administration. Serum samples were collected at baseline and at 5-, 10-, 15-, and 60-min following heparin injection. Spec cPL, Spec fPL, and lipase activities were measured using DGGR and triolein assays, whereas HTGL and LPL activities were measured using their respective assays. RESULTS: Spec cPL and Spec fPL levels showed no significant changes following heparin administration. Conversely, DGGR-based and triolein-based lipase activities, as well as HTGL and LPL activities, were significantly increased after heparin administration in both dogs and cats. HTGL and LPL activities showed significant positive correlations with DGGR-based (P&#x2009;<&#x2009;.001, r&#x2009;=&#x2009;.90 for both) and triolein-based (P&#x2009;<&#x2009;.001, r&#x2009;=&#x2009;.63 and P&#x2009;<&#x2009;.001, r&#x2009;=&#x2009;.68, respectively) lipase activities, but not with Spec cPL and Spec fPL. CONCLUSIONS: DGGR- and triolein-based lipase activities are influenced by HTGL and LPL activities, as their substrates are hydrolyzed by pancreatic lipase, HTGL, and LPL.