[Stress responsiveness of the hypophyseal-adrenocortical system in rats with active and passive types of behaviour].

No linear differences in the corticosterone basal levels or in its changes following weak stress effects were revealed in rats with active (KHA) or passive (KLA) behavioural strategy. A strong immobilisation stress alone was able to evoke significant linear differences in the hypophyseal-adrenocortical system's responsiveness. The hormonal response to stress was prolonged in the KHA rats as the increased level of corticosterone in the blood of these animals was longer preserved than in the KLA rats. The results suggest both a different sensitivity of the hypophyseal-adrenocortical system and a different velocity of the stress response deactivation in active and in passive animals.