Effect of unilateral adrenalectomy on acute immobilization stress response in rats

The aim of the present study was to investigate the differential effect of unilateral adrenalectomy, right vs. left, in response to acute immobilization stress (IS) in rats.

Adult male rats were subjected to unilateral right or left adrenalectomy or sham operation (control). Two weeks later, the rats were sacrificed either immediately or 3 hours after IS exposure. Plasma samples were used for determination of catecholamines (CAs), adrenocorticotrophic hormone (ACTH), corticosterone (CORT), sodium, potassium, and glucose levels. After terminating the experiment, both or remaining adrenals were removed, weighed, and used for estimation of CAs and nitric oxide (NO) levels.

Under basal conditions, either right or left adrenal kept all the tested parameters near to the control levels, except the adrenal weight and CAs content. These were significantly higher in the remaining right than left adrenal. However, the remaining right adrenal responded better to IS exposure than the remaining left one in the term of compensatory adrenal growth and plasma parameters which were all kept insignificantly different from those of IS intact group.

Our data indicate that the adrenal glands may substitute each other under basal conditions. However, the right adrenal seems to be dominant during exposure to acute immobilization stress.