Adrenal cortical function following stepwise removal of the brain in the dog

¹ Division of Neurosurgery, Department of Surgery and Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota

Previous studies indicate that hypothalamic lesions will prevent adrenal cortical response to stress. The present study was undertaken to determine if higher centers of the brain are necessary for adrenal cortical hypersecretion of 17-hydroxycorticosteroids due to operative trauma. Intermittent samples of adrenal venous blood were obtained from dogs by means of adrenal cannulas and 17-hydroxycorticosteroid output was determined. Stepwise removal of the brain was performed, with collections of adrenal venous blood at various levels of anatomic integrity. Removal of the brain down to the hypothalamus resulted in no diminution in the maximal adrenal cortical response following operative trauma as measured by 17-OH-corticosteroid output. After removal of the hypothalamus there is a persistence of adrenal corticoid secretion up to 6 hours after removal of this structure leaving the pituitary gland intact. It is concluded that a) the CNS above the hypothalamus is not essential for adrenal 17-OH-corticosteroid production in response to operative trauma; and b) adrenal cortical secretion persists in response to stress up to 6 hours after removal of the hypothalamus.