Measurement of salivary cortisol in guinea pigs

For collection of saliva, cotton buds (Q-tips) were inserted into the guinea pig's cheek pouch, parallel with the cheek teeth. Within 5 minutes, sufficient fluid was collected for salivary cortisol measurements. Salivary cortisol was about 7 ng/ml after intramuscular (i.m.) injection of 0.2 ml saline. Compared with saline treatment, it was drastically increased after i.m. injection of ACTH or cortisol. Taking into account the close relationship between the amounts of cortisol in saliva and plasma in cortisol- or ACTH-treated animals, we conclude that measuring saliva cortisol offers promise as a noninvasive method to monitor the changes of adrenocortical function in guinea pigs.