The present study investigated the relationship between supraphysiological plasma concentrations of adrenaline and the resulting haemodynamic and metabolic effects. Adrenaline was administered at five infusion rates (0.01-0.2 micrograms kg-1 min-1) in an escalating sequence to eight volunteers. The arterial plasma concentration of adrenaline increased from 53 +/- 44 to 4349 +/- 818 ng litre-1 during the highest infusion rate. Typical haemodynamic responses, such as increase in blood pressure and heart rate, were seen. The plasma concentrations of glucose and lactate increased from 5.2 +/- 0.4 to 13.7 +/- 1.3 mmol litre-1 and from 0.9 +/- 0.3 to 4.7 +/- 2.6 mmol litre-1, respectively, during the highest infusion rate without a significant increase in insulin concentration. Non-esterified fatty acids increased from 379 +/- 97 to 1114 +/- 331 mumol litre-1 during the 0.06 microgram kg-1 min-1 infusion rate. Adrenaline had no selective haemodynamic effect. If similar metabolic effects occur in patients during treatment with adrenaline or other sympathomimetics, they may further increase breakdown of energy stores in a situation of increased catabolism, and impair utilization of parenteral nutrition.