role of autonomic innervation of the adrenal gland on the expression of corticosterone diurnal rhythm

ABSTRACT

Several lines of evidence indicate that alterations in sympathetic input to the adrenal gland may represent one of the routes by which adrenal responsiveness to circulating adrenocortico-trophic hormone [ACTH] is modulated. This study is designed to evaluate the role of autonomic innervation of the adrenal gland on the expression of corticosterone diurnal rhythm. This work was done on forty [40] rats divided into 3 groups. Group I is resting control group. Group II is divided into 2 subgroups. Subgroup II a was injected with dexamethasone while subgroup II b treated with dexamethasone and ACTH. Group III is splanchnicotomy group. Plasma corticosterone level was measured in blood samples from all groups at AM and PM. In dexarnethasone-treated rats, dexarnethasone reduced PM level of corticosterone without significant change in AM corticosterone level when exogenous ACTH was given to dexamethasone treated rats, corticosterone response was found to be without significant AM/PM difference. In splanchnic nerve transection group, splanchnicotomy resulted in a non significant change in AM corticosterone level, while PM corticosterone level reduced significantly. This result indicates that splanchnic neural input to adrenal gland facilitates resting PM corticosterone secretion