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 105 disintegrations/min (dpm) · kg-1 · min-1] could be accurately predicted (2.14 ± 0.32 x 105 dpm · kg-1 · min-1) 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 < 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.
|Original language||English (US)|
|Journal||American Journal of Physiology - Endocrinology and Metabolism|
|State||Published - Jan 1 1988|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Physiology (medical)