Steroidogenesis in patients with adrenal incidentalomas: Extended steroid profile measured by liquid chromatography-mass spectrometry after ACTH stimulation and dexamethasone suppression.

Abstract

Describe the secretion and profile of adrenal steroids in patients with adrenal incidentalomas compared to control subjects. A prospective study, 73 patients with adrenal incidentalomas, 21 bilateral and 52 unilateral and 34 matched controls in University Hospital. Collect fasting blood sample before and 60min after ACTH test (250µg IV). One week later, perform overnight 1mg dexamethasone test. The following steroids were measured by liquid chromatography-mass spectrometry (LC-MS): pregnenolone, 17-OH pregnenolone, 17-OH progesterone, 11-deoxycorticosterone, 11-deoxyortisol, 21-deoxycortisol, corticosterone, cortisol, androstenedione and aldosterone. Mean baseline serum cortisol was higher in incidentalomas, bilateral 361±124, (range 143-665)nmol/L,(p<.0001), unilateral 268±89 3.2 (range 98-507)nmol/L (p<.019) compared to controls 207±100 (range 72-502)nmol/L. ACTH stimulation showed significantly higher levels in bilateral and unilateral cases compared to controls. After dexamethasone, mean serum cortisol levels suppressed in bilaterals 89±69 (range 30-3)nmol/L (p<.0001), 58±52 (range 16-323)nmol/L in unilateral (p<.01) compared to 26±9 (range 7-46)nmol/L in controls. Mean baseline serum corticosterone was higher in bilateral 9.3±4.8 (range 2.4-18.4)nmol/L (p<.005) and unilateral 7.3±5.7 (range 0.1-30.3)nmol/L (p<.01) compared to controls 4.2±2.4 (range 1.1-10.2)nmol/L, after ACTH stimulation significantly increased to higher levels in bilateral (p<.0002) and unilateral cases (p<.044) compared to controls. After dexamethasone, mean levels were 2.5±2.6 (range 0.5-12.5)nmol/L in bilateral (p<.0006), 1.5±1.6 (range 0.3-9.3)nmol/L in unilateral (p<.09) and 0.75±0.46 (range 0.1-2.1)nmol/L in controls. Mean baseline serum 11-deoxycorticosterone (DOC) was higher in bilaterals 0.32±0.23 (range 0.08-1.1)nmol/L (p<.03) compared to controls 0.15±0.21 (range 0.08-1.1)nmol/L. ACTH stimulation increased levels to 3.27±1.72 (range 0.5-7.4)nmol/L in bilateral cases compared to controls 1.369±1.53 (range 0.1-7.1)nmol/L (p<.0001). Dexamethasone decreased levels to baseline (p ns). There were significant differences in serum 21-deoxycortisol (p<.0002) and serum pregnenolone (p<.004) only after ACTH stimulation. There is increased activity in several steroid biosynthesis pathways and higher steroid levels in bilateral compared to unilateral cases and evidence of hypercortisolism in 30% unilateral and 62% of bilateral incidentalomas.