Like somatostatin receptors, dopamine receptors are widely expressed in normal neuro-endocrine tissues and pituitary adenomas, including approximately 80 % of corticotroph adenomas [48, 49]. Five dopamine receptor subtypes have been characterized, usually classified as D1-like or D2-like, with most D2-like receptors associated with inhibitory actions [50]. The dopamine agonists bromocriptine and cabergoline have both been used to treat pituitary adenomas; however, cabergoline is more selective at D2 receptors and has been found to be more effective and better tolerated than bromocriptine in women receiving treatment for hyperprolactinemia [51].