Evaluation of hypothalamo-pituitary-adrenal activity in the tree shrew (Tupaia belangeri) via salivary cortisol measurement

Saliva sampling is frequently used in humans for adrenal glucocorticoid hor mone analysis because of advantages such as non-invasiveness, the ease of c ollection, and storing of the samples. To transfer this advantageous method to laboratory mammals, potentially confounding factors such as stressful h andling procedures have to be excluded. In the present study we established a method for collecting saliva for cortisol measurement in freely moving a dult male tree shrews (Tupaia belangeri). The practicability of the procedu re was demonstrated (i) by stress-induced changes in cortisol levels reveal ing a significant increase during the stress phase (control = 0.91 nmol/l v s stress = 1.71 nmol/l), and (ii) by reporting no significant differences i n salivary cortisol levels before and after performance of a learning task. The present study emphasizes the use of salivary cortisol analysis especia lly for monitoring acute changes in the hypothalamo-pituitary-adrenal axis activity in male tree shrews.