Kiyomi Nakajima1, Tetsuo Machida1, Shigeyuki Imamura2, Daisuke Kawase3, Kazuya Miyashita3, Isamu Fukamachi3, Masahiro Maeda3, Yuji Muraba4, Takafumi Koga4, Junji Kobayashi5, Takao Kimura1, Katsuyuki Nakajima6, Masami Murakami1. 1. Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan. 2. Imamura Enzyme Technology Laboratory, Shizuoka, Japan. 3. Immuno-Biological Laboratories, Fujioka, Gunma, Japan. 4. Hidaka Hospital, Takasaki, Gunma, Japan. 5. Department of General Internal Medicine, Kanazawa Medical University, Kanazawa, Japan. 6. Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; Hidaka Hospital, Takasaki, Gunma, Japan; Department of General Internal Medicine, Kanazawa Medical University, Kanazawa, Japan. Electronic address: nakajimak05@ybb.ne.jp.
Abstract
BACKGROUND: Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) play a central role in triglyceride-rich lipoprotein metabolism by catalyzing the hydrolysis of triglycerides. Quantification of LPL and HTGL activity is useful for diagnosing lipid disorders, but there has been no automated method for measuring these lipase activities. METHODS: The automated kinetic colorimetric method was used for assaying LPL and HTGL activity in the post-heparin plasma using the natural long-chain fatty acid 2-diglyceride as a substrate. LPL activity was determined with apoCII and HTGL activity was determined without apoCII with 2 channel of auto-analyzer. RESULTS: The calibration curve for dilution tests of the LPL and HTGL activity assay ranged from 0.0 to 500 U/L. Within-run CV was obtained within a range of 5%. No interference was observed in the testing of specimens containing potentially interfering substances. The measurement range of LPL activity in the post-heparin plasma was 30-153 U/L, while HTGL activity was 135-431 U/L in normal controls. CONCLUSIONS: The L PL and HTGL activity assays are applicable to quantitating the LPL and HTGL activity in the post-heparin plasma. This assay is more convenient and faster than radiochemical assay and highly suitable for the detection of lipid disorders.
BACKGROUND:Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) play a central role in triglyceride-rich lipoprotein metabolism by catalyzing the hydrolysis of triglycerides. Quantification of LPL and HTGL activity is useful for diagnosing lipid disorders, but there has been no automated method for measuring these lipase activities. METHODS: The automated kinetic colorimetric method was used for assaying LPL and HTGL activity in the post-heparin plasma using the natural long-chain fatty acid2-diglyceride as a substrate. LPL activity was determined with apoCII and HTGL activity was determined without apoCII with 2 channel of auto-analyzer. RESULTS: The calibration curve for dilution tests of the LPL and HTGL activity assay ranged from 0.0 to 500 U/L. Within-run CV was obtained within a range of 5%. No interference was observed in the testing of specimens containing potentially interfering substances. The measurement range of LPL activity in the post-heparin plasma was 30-153 U/L, while HTGL activity was 135-431 U/L in normal controls. CONCLUSIONS: The L PL and HTGL activity assays are applicable to quantitating the LPL and HTGL activity in the post-heparin plasma. This assay is more convenient and faster than radiochemical assay and highly suitable for the detection of lipid disorders.