EFFECT OF ACUTE STRESS ON PLASMA-LEVELS O F CATECHOLAMINES, CORTISOL AND METABOLITES IN STRESS-SUSCEPTIBLE GROWING PIGS

The purpose of this study was to show the behaviour of the plasma leve l of catecholamines in stress-susceptible pigs during an acute stress and to gain new insights in the role of catecholamines in the initiati on of malignant hyperthermia. Therefore, a halothane challenge test wa s performed in stress- susceptible growing pigs, and the changes of ha ematocrit, hormones and metabolites were monitored during the handling before the test, during halothane exposure and thereafter. Already in connection with the handling before the test, haematocrit values and plasma levels of epinephrine, norepinephrine, glucose, lactate and pot assium increased significantly. However, the plasma concentration of c ortisol and free glycerol increased gradually and the level of noneste rified fatty acids did not show any changes. Wh:le the levels of catec holamines and potassium decreased already during halothane exposure, h aematocrit values and concentrations of glucose and lactate continued to increase. The present results indicate that the catecholamines are not involved in the initiation of malignant hyperthermia.