Septal Lesions and Resting Adrenal Function. A Possible Explanation of Conflicting Findings

Plasma corticosterone values were obtained using cortico-sterone-binding-globulin florisil assay for normal, sham-lesioned and septal-lesioned rats at 2 time periods, 12 h apart, corresponding to 2 h after the switch to light or dark under a 12:12 h light:dark regime. At a time 2 h after the switch to light, when normal and sham-lesioned animals evidenced low resting corticosterone responses, septal rats exhibited a fivefold increase in resting corticosterone levels compared to non-lesioned animals. At a time 2 h after the switch to dark, when basal corticosterone values are higher, normal, sham-lesioned and lesioned rats evidence no differences in their plasma corticosterone levels. Results suggest that the 24 h plasma-corticosterone rhythm is altered in rats following septal damage.