Laboratory handling and its influence on hormonal and metabolic parameters during acute inflammation in rats. A critique of long-term treatment by repeated injections.

Twice a day, rats were exposed to handling stress by sham i.p. injections during a period of five days. This procedure progressively drove up the basic blood levels of free adrenaline, noradrenaline and dopamine, while insulin decreased to below normal. Blood glucose returned successively from hyperglycemia during the beginning of the experiment to normal later on. If rats subjected to acute inflammation were handled, the parameters blood catecholamines, glucose and the lymphocyte ingress into the site of inflammation all showed the same patterns of changes, suggesting a certain synchronization of the metabolic events. This synchronization failed to occur in animals with inflammation, but without handling. In any case, the disturbed metabolism of handled animals did not normalize during the test period of five days. Therefore, application of test substances by repeated injections is a useless method for the correct investigation of chronic exogenous influences.