Plasma levels of atrial natriuretic hormone in Cushing's syndrome.

To examine a possible role for atrial natriuretic hormone (ANH) in the water and electrolyte disturbances associated with hypercortisolism, plasma ANH levels were measured in 18 patients with endogenous Cushing's syndrome. Nine patients had elevated plasma ANH levels compared to normal subjects. The mean plasma ANH concentration [72.5 +/- 13.0 (+/- SE) pg/mL (23.5 +/- 4.2 pmol/L)] in the Cushing's syndrome patients was significantly higher than that in 40 normal subjects [37.6 +/- 1.9 pg/mL (12.2 +/- 0.62 pmol/L)]. A significant positive correlation was found between plasma ANH and cortisol levels in individual patients. There were no significant correlations, on the other hand, between plasma ANH concentrations and PRA, plasma aldosterone levels, or mean blood pressure. After treatment, plasma ANH concentrations decreased in all 6 patients who had elevated plasma ANH levels preoperatively. In 1 patient with Cushing's disease, plasma ANH levels changed in parallel with plasma cortisol concentrations during o,p'DDD treatment. Fifteen patients who were receiving long term synthetic glucocorticoid therapy for the treatment of miscellaneous diseases had a significantly higher mean plasma ANH level [50.2 +/- 4.0 (+/- SE) pg/mL (16.3 +/- 1.3 pmol/L)] than that in normal subjects. These results suggest that plasma ANH levels are elevated in a substantial number of patients with Cushing's syndrome due to either a direct stimulatory effect of glucocorticoid on atrial ANH secretion or, alternatively, intravascular volume expansion resulting from excessive cortisol secretion.