Objective: Adrenal insufficiency is a life-threatening disease and therefore, accurate diagnosis and prompt treatment are life-saving. The main purpose of this study was to retrospectively evaluate the serum cortisol levels measured during the L-dopa test in cases suspected GH deficiency and to compare the effect of L-dopa on cortisol secretion with the results of previous studies.

Method: Between January 2019 and January 2021, patients who underwent the L-dopa test for the evaluation of GH deficiency in our Pediatric Endocrinology Clinic and whose basal cortisol levels were measured at the baseline and at the 120th minutes of the test were included. The clinical, anthropometric, and laboratory data of the patients were obtained from the medical records.

Results: Eighty-five patients (38 girls, 47 boys) were included in the study. The mean age of the patients was 10.3 ± 3.5 years (range, 4.1 - 14.9 years). The mean serum cortisol level was 11.1 ± 3.6 µg/dL at baseline and 20.9 ± 3.8 µg/dL at 120th minutes (the mean cortisol increase was 9.8 ± 4.1 µg/dL). Cortisol response was adequate (> 18 µg / dL) in 76 cases (89.4%). Nausea/vomiting was observed in 53 (62.4%) of the patients during the L-dopa test. Peak cortisol responses of the cases with and without side effects were similar (20.9 ± 3.8; 20.8 ± 3.7; p = 0.945).

Conclusion: In conclusion, the L-dopa test is easy to apply, effective, and safe and can be performed to evaluate cortisol adequacy at least in patients being evaluated for suspected GH deficiency.

Keywords: Adrenal function, adrenal insufficiency, cortisol, cortisol deficiency, dopamine agonist, L-dopa