Protocol for efficient plasma sampling for low density lipoprotein turnover studies.

Abstract

Radiolabeled low density lipoprotein (LDL) is commonly used to study the turnover of LDL apolipoprotein B (apoB), the major protein component of LDL. Following an intravenous injection of radioiodinated LDL, typical sampling schedules have including 20-25 samples over a 14-day period with frequent sampling during the first 12 hr and daily samples thereafter. This is a burdensome task for subjects and investigators. To improve acceptance of the procedure, we have examined the effects of reduced sampling schedules upon the estimation of the fractional catabolic rate (FCR) for LDL apoB. Data from 36 different sets of LDL decay curves obtained from investigations of subjects with a variety of lipoprotein phenotypes have been used to test these schedules. Our results indicate that by choosing specific intervals over a 14-day period only 10 samples are sufficient to accurately determine the fractional catabolic rate for LDL in plasma. This reduced sampling schedule should facilitate the study of LDL turnover in large groups of subjects as outpatients.