| Abstract: | High-performance gel exclusion chromatography using flow-through radioactivity monitoring was employed for rapid measurement of low-density lipoprotein (LDL) turnover. Iodinated LDL was injected into five fasting rabbits. Serial blood samples were obtained and small aliquots (0.1-0.2 ml) were injected into the chromatographic system using 0.2 M Tris-acetate buffer (pH 7.0). Radioactivity in lipoproteins was measured by an on-line gamma counter (Flo-One) attached to the high-performance liquid chromatograph and in a regular gamma counter after collecting the fractions. Sequential ultracentrifugation was also used to separate lipoproteins, and the radioactivity in each fraction was measured. The Flo-One method was faster; however, the efficiency of Flo-One varied with the amount of radioactivity and therefore it was necessary to inject the same amount of radioactivity to get comparable values. |
