To study the changes of hearing and hormones of hypothalamic pituitary adrenal axis (HPA axis) in rats with internal ear ischemia induced by continuing intravenous administration of adrenalin.Methods24 male Wistar rats were equally divided into 3 groups randomly, i.e. low dose group (8 μg·kg1·min1), high dose group (12 μg·kg1·min1) and control group. Adrenalin was administrated systemically from the caudal vein for 3 hours. The control group was treated with equal volume of normal saline. Click evoked auditory brainstem response (ABR) was measured before administration, 3 hours after infusion and the next day. The concentration of corticotropin releasing factor (CRF), adrenocorticotropic hormone (ACTH) and glucocorticoid GC was measured by ELISA.ResultsAfter administration, the thresholds of waveⅠ, wave Ⅲ of the two adrenalin groups were significantly elevated, while the amplitudes of wave Ⅲ at 40 dB of the adrenalin groups were significantly descended. The auditory thresholds and amplitudes recovered at the next day after administration. The serum concentration of CRF, ACTH, GC of the low dose group increased significantly over the control group.ConclusionSystemic continuing adrenalin administration can induce reversible hearing loss and increase in CRF, ACTH and GC in rats.