[The reactivity of the hypophyseal-adrenal system in the suslik Citellus erythrogenus major awaking from hibernation]

Abstract

It has been shown that corticosteroid content of the blood in hibernating ground squirrels is the lowest. In spring, before the arousal, some increase in corticosteroid content is observed, although the latter remains lower than that in non-hibernating animals. During the arousal, corticosteroid content of the blood in the ground squirrels increased slowly and gradually. It is suggested that warming is not a stress factor for the arousing ground squirrels. The hypothalamo-hypophyseal-suprarenal system of hibernating ground squirrels is also insensitive to the additional stimulation of the adrenergic mechanisms by novodrin. However, functional activity of the system hypophysis-suprarenal cortex in the arousing ground squirrels is rather high: inhibition of warming by propranolol, serotonin and 5-hydroxytryptophan results in significant stimulation of this system.