Psychologic and Neural Regulation of Growth Hormone Secretion

&NA; A wide variety of stressful stimuli, both physical and psychologic, cause GH discharge in both man and monkey in a manner reminiscent of the changes in ACTH secretion under similar circumstances. The hypothalamus appears to mediate acute changes in GH release as evidenced by the finding that basal hypothalamic or infundibular lesions and pituitary stalk section blocked the acute GH response to hypoglycemia in rat, monkey and man. Changes in GH release in hypoglycemia, prolonged fasting and exercise after meals are related to caloric homeostasis. GH elevation, after stressful stimuli, may produce metabolic effects related to caloric requirements and has protective effects on tissues. The mechanisms for growth hormone release and adrenal corticoid activation are independent since dissociation of these two responses is found after a variety of stimuli in man and monkey. Growth hormone and adrenal discharge appear to have specific independent psychologic correlates.