Plasma palmitate turnover in subjects with thermal injury

Using a continuous infusion of [1-¹³C] palmitic acid tracer, plasma palmitate turnover was measured 14 times in nine bandaged, thermally injured adults. Plasma glucose (102 ± 4 mg/dl), insulin (21 ± 4 /µU/ml), and glucagon (296 ± 34 pg/ml) levels were significantly elevated compared with values in uninjured controls. Circulating plasma epinephrine (67 ±11 pg/ml) and norepinephrine (219 ± 57 pg/ml) levels were more than twofold their respective control values of 261 ± 4 pg/ml and 211 ± 7 pg/ml but less than the previously defined plasma threshold levels for lipolytic effects of these catecholamines as circulating hormones. Plasma palmitate and free fatty acid concentrations, 113 ± 8 and 452 ± 38 /µM, respectively, were not different from control values but palmitate flux (2.66 ± 0.28 µmol kg^-1min^-1) and free fatty acid turnover calculated therefrom (10.53 ± 1.13 µmol kg^-1min^-1) were significantly elevated compared to the control rates. While palmitate turnover significantly correlated with plasma palmitate concentration and with per cent body surface area burned, there was no relationship between palmitate flux and circulating epinephrine or norepinephrine levels. These data raise new questions about the relative catabolic roles of catecholamines in bandaged, thermally-injured patients.