THE CHARACTERISTICS OF PLASMA ACTH, SERUM CORTISOL AND UFC IN 136 PATIENTS WITH CUSHING SYNDROME / 解放军医学杂志

ABSTRACT

To evaluate the significance of plasma ACTH (pACTH), serum cortisol (SC) and urinary free cortisol UFC as well as low or high dose dexamethasone suppression test in Cushing syndrome, the levels of hormones were evaluated in 136 cases of Cushing syndrome. It was found that the levels of SC and UFC were elevated in almost all the 121 patients with Cushing syndrome. The mean levels of pACTH were higher in 86 patients with Cushing disease and lower in 36 cases with adrenocortical tumor or ACTH independent nodular adrenocortical hyperplasia (AINAH) than those in normal subjects. The ACTH levels might be in normal range in many patients with Cushing syndrome, but they were higher in patients with Cushing disease and lower in the patients with adrenocortical tumor or AINAH than those of the high limit at ACTH0am in normal subjects. It was a common feature that the diurnal rhythm of hormone secretion disappeared and the hormone levels were not suppressed by low dose dexamethasone suppression test in the patients with Cushing syndrome. In more than 90% of the patients with adrenocortical tumor or AINAH the levels of SC and UFC were not suppressed by high dose dexamethasone. In 12 of clinically cured patients with Cushing disease the levels of pACTH8am, SC8am and UFC were normal or even low. The pACTH levels were low in two patients with iatrogenic Cushing syndrome. The results suggested that examinations of SC, UFC and low dose dexamethasone suppression test were very important in the diagnosis of Cushing syndrome. The pACTH level was a key parameter to distinguish Cushing disease from adrenocortical tumor or AINAH.