TY - JOUR
T1 - Determination of Plasma-Free Fatty Acid Kinetics with Tracers
T2 - Methodologic Considerations
AU - Miles, J. M.
AU - Jensen, M. D.
PY - 1991/5
Y1 - 1991/5
N2 - Plasma-free fatty acids (FFA) are an important source of energy for a variety of tissues. Recently, there has been an increased interest in the measurement of FFA kinetics in vivo, using radiolabeled or stable isotopic tracers. Standard techniques for measurement of FFA-specific activity are relatively imprecise and have limited sensitivity. We have developed a method for determination of the concentration and specific activity of individual plasma FFA that is precise (coefficient of variation <2%) and sensitive (detection limit in the high femptomolar to low picomolar range). Using this method, one can measure the kinetics of three or more long-chain fatty acids simultaneously. Its sensitivity is a particular advantage if one wishes to measure low rates of FFA turnover such as are encountered during hyperinsulinemia. It has been suggested that, for optimal accuracy in the determination of substrate kinetics, the tracer should be administered in the left ventricle and mixed venous blood samples should be obtained from the right heart. We have conducted experiments in dogs which demonstrate that peripheral tracer infusion and more conventional arterial (or arterialized venous) sampling actually provide more accurate estimates of FFA turnover; this is fortunate, since intracardiac infusion and sampling are not practical for human studies.
AB - Plasma-free fatty acids (FFA) are an important source of energy for a variety of tissues. Recently, there has been an increased interest in the measurement of FFA kinetics in vivo, using radiolabeled or stable isotopic tracers. Standard techniques for measurement of FFA-specific activity are relatively imprecise and have limited sensitivity. We have developed a method for determination of the concentration and specific activity of individual plasma FFA that is precise (coefficient of variation <2%) and sensitive (detection limit in the high femptomolar to low picomolar range). Using this method, one can measure the kinetics of three or more long-chain fatty acids simultaneously. Its sensitivity is a particular advantage if one wishes to measure low rates of FFA turnover such as are encountered during hyperinsulinemia. It has been suggested that, for optimal accuracy in the determination of substrate kinetics, the tracer should be administered in the left ventricle and mixed venous blood samples should be obtained from the right heart. We have conducted experiments in dogs which demonstrate that peripheral tracer infusion and more conventional arterial (or arterialized venous) sampling actually provide more accurate estimates of FFA turnover; this is fortunate, since intracardiac infusion and sampling are not practical for human studies.
UR - http://www.scopus.com/inward/record.url?scp=0026091292&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026091292&partnerID=8YFLogxK
U2 - 10.1177/014860719101500390S
DO - 10.1177/014860719101500390S
M3 - Article
C2 - 1865566
AN - SCOPUS:0026091292
SN - 0148-6071
VL - 15
SP - 90S-93S
JO - Journal of Parenteral and Enteral Nutrition
JF - Journal of Parenteral and Enteral Nutrition
IS - 3
ER -