Choice of infusion-sampling mode for tracer studies of free fatty acid metabolism

Am J Physiol. 1988 May;254(5 Pt 1):E562-5. doi: 10.1152/ajpendo.1988.254.5.E562.


To determine the preferred infusion-sampling mode for isotopic studies of free fatty acid (FFA) metabolism, tracer [( 14C]palmitate) was infused into the left ventricle of five anesthetized dogs, and tracee ([3H]palmitate) was infused into three separate peripheral veins of each dog. The [14C]palmitate specific activity (SA) was lower in mixed venous than arterial blood, and [3H]palmitate SA was equal in both sites. The actual infusion rate of [3H]palmitate [2.15 +/- 0.31 X 10(5) disintegrations/min (dpm).kg-1.min-1] could be accurately predicted (2.14 +/- 0.32 X 10(5) using the known [14C]palmitate infusion rate and the arterial plasma [14C]-to-[3H]palmitate ratio. In contrast, the mixed venous [14C]-to-[3H]palmitate ratio resulted in overestimates (P less than 0.05) of the actual [3H]palmitate infusion rate. In summary, venous tracer infusion with arterial blood sampling for FFA tracer studies provides the most accurate estimates of tracee rate of appearance.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Carbon Radioisotopes
  • Chromatography, High Pressure Liquid
  • Dogs
  • Fatty Acids, Nonesterified / blood*
  • Palmitic Acid
  • Palmitic Acids / administration & dosage
  • Palmitic Acids / blood
  • Radioactive Tracers / administration & dosage*
  • Radioisotopes / administration & dosage*
  • Tritium


  • Carbon Radioisotopes
  • Fatty Acids, Nonesterified
  • Palmitic Acids
  • Radioactive Tracers
  • Radioisotopes
  • Tritium
  • Palmitic Acid