Catecholamine binding and concentrations in acute phase plasma after surgery.

The present study was undertaken to decide whether the bound fractions and/or total concentrations of catecholamines were determinative for the variability of biologically active concentrations in human plasma. The binding and concentrations of noradrenaline (NA) and adrenalin (Adr) were determined in acute phase plasma after major hip surgery in five subjects. The bound fractions before surgery were 23.0% and 18.4% for NA and Adr, respectively. The binding of catecholamines increased in the post-operative period. Five days after surgery the binding of NA and Adr was 30.9% and 24.0%, respectively. The surgical trauma induced an acute phase reaction in plasma with a decrease of albumin (HSA) concentrations whereas the concentrations of alpha-1 acid glycoprotein (AAG) increased. The catecholamine concentrations showed a considerable inter- and intraindividual variability. However, the present work shows that the variability of the biologically active catecholamine concentrations is mainly dependent on the total plasma concentrations and not the plasma protein binding.