Free fatty acid turnover and oxidation after burn shock in guinea pigs

We have previously shown a rapid decrease in plasma free fatty acid (FFA) concentration and turnover rate immediately after extensive full-skin-thickness burn in a guinea pig model. In the present study the relationship between plasma FFA turnover rate and oxidation after burn was investigated, since the amount of plasma FFA oxidized is determined by the turnover rate and the percent of turnover that is oxidized. Using the constant infusion of 14C-palmitate, we examined the plasma FFA concentration and turnover rate, plasma FFA contribution to carbon dioxide production, percent of plasma FFA turnover that is rapidly oxidized to carbon dioxide, oxygen consumption, carbon dioxide production, and respiratory quotient. We found that in some cases, but not all, plasma FFA concentration and turnover rate were decreased 1-6 hours postburn. Both in the presence or absence of decreased FFA turnover rate, the percent of FFA turnover that was immediately oxidized to carbon dioxide was unchanged. After burn shock, the rate of oxidation of FFA appears to be controlled by the rate of FFA delivery to the tissues.