O. Mansoor et al., ALBUMIN AND FIBRINOGEN SYNTHESES INCREASE WHILE MUSCLE PROTEIN-SYNTHESIS DECREASES IN HEAD-INJURED PATIENTS, American journal of physiology: endocrinology and metabolism, 36(5), 1997, pp. 898-902
The effect of trauma on protein metabolism was investigated in the who
le body, muscle, and Liver in severely head-injured patients presentin
g an acute inflammatory response by comparison to fed control subjects
receiving a similar diet. Nonoxidative leucine disposal(an index of w
hole body protein synthesis) and muscle, albumin, and fibrinogen synth
esis were determined by means of a primed, continuous infusion of L-[1
-C-13]leucine. Nonoxidative leucine disposal increased by 28% in the p
atients (P < 0.02). Fractional muscle protein synthesis rate decreased
by 50% (P < 0.01) after injury. Fractional and absolute fribrinogen s
ynthesis rates were multiplied by two and nine, respectively, after in
jury (P < 0.001). Albumin levels piers lower in patients (25.2 +/- 1.2
g/l, means +/- SE) than in controls (33.7 +/- 1.2 g/l, P < 0.001). ho
wever, fractional albumin synthesis rates were increased by 60% in pat
ients (11.4 +/- 1.0%/day) compared with controls (7.3 +/- 0.4%/day, P
< 0.01). Therefore, 1) head trauma induces opposite and large changes
of protein synthesis in muscle and acute-phase hepatic proteins, proba
bly mediated by cytokines, glucocorticoids, and other stress hormones,
and 2) in these patients, hypoalbuminemia is not due to a depressed a
lbumin synthesis.