Subtyping of primary aldosteronism by adrenal vein sampling: effect of acute D2 receptor dopaminergic blockade on adrenal vein cortisol and chromogranin A levels

Background: Adrenal vein sampling (AVS) is the gold standard for identifying the surgically curable forms of primary aldosteronism. Dopamine modulates adrenocortical steroidogenesis and tonically inhibits aldosterone secretion via D-2 receptor. However, whether it could also affect the release of cortisol and chromogranin A (ChA), which can be used to assess the selectivity of AVS, is unknown. Objective: To investigate whether metoclopramide increased the release of cortisol and ChA and could thereby improve assessment of the selectivity at AVS. Design and methods: We investigated the effect of acute D-2 antagonism with metoclopramide on cortisol and ChA release from the adrenal gland by comparing the adrenal vein and infrarenal inferior vena cava (IVC) hormone levels at baseline and after metoclopramide administration in 34 consecutive patients undergoing AVS. Results: Metoclopramide increased plasma aldosterone in the IVC (P < 0.00001) and in the adrenal vein blood (P < 0.002) but failed to increase plasma cortisol concentration or ChA levels. Therefore, it did not increase the selectivity index based on the measurement of either hormone. Conclusions: This study shows that the release of cortisol and ChA is not subjected to tonic D2 dopaminergic inhibition. Therefore, these findings lend no evidence for the usefulness of acute metoclopramide administration for enhancing the assessment of the selectivity of blood sampling during AVS with the use of either cortisol or ChA assay.