Endocrine Abstracts

Introduction: The aim of this study was to evaluate the worth of the salivary cortisol after overnight 1 mg dexamethasone suppression test (DST) in different patients.

Materials and methods: The patient groups of the study consisted of 18 Cushing’s syndrome patients, 12 patients with non-functional adrenal incidentaloma, 37 patients with obesity, 16 patients with hirsutism and 26 healthy control patients. Salivary cortisol (SC) and plasma cortisol after 1 mg-overnight DST were measured. SC was measured with luminescense immunoassay kit.

Results: Salivary cortisol levels after overnight DST was found significantly different between all groups (P<0.05) except between patients with hirsutism and obesity and between patients with adrenal incidentaloma and healthy control group (P=0.357). In this context, plasma cortisol levels after overnight DST were not significantly different between patients with hirsutism and control group and between patients with obesity and control patients both, while it was significantly different between all the other groups.

When all the patient groups are evaluated in a whole group there was a significant positive correlation between plasma and salivary cortisol (r=0.542, P=0.0001). In the subgroup analyses, there was no correlation between salivary and plasma cortisol in patients with hirsutism and Cushing’s syndrome. In the groups with adrenal incidentaloma and healthy control, highly significant correlation between salivary and plasma cortisol was found (r=0.750 – P=0.02, r=0.679 – P=0.008 respectively).

Conclusion: Salivary cortisol after overnight DST may be one of the new non-invasive diagnostic tools for the differential diagnosis of Cushing’s syndrome and pseudo- Cushing syndrome. However, laboratory test results and clinical findings should be evaluated together in clinical practice.