Adrenaline and psychometric mood factors: A controlled case study of two patients with bilateral adrenalectomy

Previous studies have suggested that adrenaline subserves many emotions and that adrenaline is the physiological basis for fear, but these observations have been difficult to replicate. Acute insulin-induced hypoglycaemia can be used to induce tense arousal in normal humans, and is one of the most potent stimuli for the secretion of adrenaline. Adrenalectomized Ss do not secrete adrenaline in response to hypoglycaemia, so it was hypothesized that a study of these patients might clarify the role of circulating plasma adrenaline in the generation of changes in psychometric mood states. Measurements of mood state, and plasma catecholamine concentrations were made during hypoglycaemia induced by an intravenous infusion of insulin, in 25 healthy subjects (12 male and 13 female) and in two women who had previously undergone surgical removal of both adrenal glands. Hedonic tone fell in the control subjects, but in both adrenalectomized patients hedonic tone was unaffected. Energetic arousal decreased significantly both in the control subjects and in the two adrenalectomized patients. Tense arousal rose in the control subjects to a peak which coincided with the onset of the acute autonomic reaction, identified by the onset of symptoms and the rapid rise in heart rate and sweating. Conversely, in the adrenalectomized patients no substantial change was observed in tense arousal from basal levels and it appeared to be lower before the induction of hypoglycaemia than in the control subjects. This experimental model has demonstrated that adrenaline release from the adrenal glands is a necessary requisite for the increase in tense arousal induced by hypoglycaemia and may contribute to the change in hedonic tone. The alteration in energetic arousal was unaffected and this is probably mediated by the direct effect of glucose deprivation on cerebral functioning.