Response of the Pituitary and Adrenal Glands of Sheep Subjected to Restraint Stress after Repeated Isolation Stress

The results obtained in the study showed that sheep subjected to a new stress factor (restraint) following twice-applied action of another stress factor (isolation from the flock), maximum ACTH concentration was considerably higher than in the group of sheep subjected to single restraint stress, whereas the values of maximum cortisol concentration were similar. It distinctly indicated a divergence in pituitary and adrenal gland activity during severe stress after another twice repeated stressor. The fact that cortisol concentration in blood plasma remained at a constant level during different combinations of stress factors and repetition of frequencies testifies to the autonomy of adrenal glands and their own ability to regulate cortisol release. In this case the plasma level of ACTH appears to be better than the cortisol marker of stress intensity in sheep within a wide range of stressor intensities and cortisol level is not an objective factor because its level in blood plasma does not change simultaneously. The reason for cortisol suppression release in this case is the necessity for the organism to keep a suitable rate of metabolism and control its excess during