Urinary catecholamine excretion in patients with secondary adrenocortical insufficiency

To evaluate the relationship between the secretion of cortisol and the activity of adrenal medulla in the secondary adrenocortical insufficiency, the excretion of epinephrine and norepinephrine was documented in 8 patients suffering from panhypopituitarism. Plasma levels and urinary excretion of cortisol were very low in baseline conditions, and the increase in these parameters of cortisol secretion occurring upon ACTH infusion was significantly reduced with respect to the response to ACTH documented in normal subjects. The mean value of urinary epinephrine excretion was at the lower limit of normal values, and a highly significant positive correlation was found between cortisolemia or cortisoluria and urinary epinephrine excretion in these patients. Despite a significant increase in cortisolemia and cortisoluria upon ACTH administration, this acute increase in adrenocortical activity was without any stimulatory effect on epinephrine or norepinephrine excretion. But, as in baseline conditions, a significant correlation was documented for the degree of adrenocortical activity and epinephrine excretion on the day of ACTH administration. It appears, therefore, that in severe secondary adrenocortical insufficiency the excretion of epinephrine is reduced proportionally to the decrease in adrenocortical activity.