Effect of injectable bromocriptine in patients with Cushing's disease

The therapeutic efficacy of sustained dopaminergic stimulation in Cushing's disease (CD), was investigated performing a three-month trial with monthly 50-100 mg injections of a bromocriptine depot preparation (Parlodel LAR, Sandoz) in six patients with CD. Dopaminergic treatment did not consistently influence pituitary-adrenal activity, as judged by plasma ACTH, cortisol and urinary free cortisol levels as well as by clinical findings. Interestingly, treatment with bromocriptine was associated with reappearance of menses in the three patients who were amenorrheic. In the five patients submitted to inferior petrosal sinus sampling, a parallelism between ACTH and PRL concentrations could be observed with a PRL rise, ipsilateral to that of ACTH, ensuing in three patients after administration of corticotropin-releasing hormone. In one patient a 55% reduction in the size of the pituitary adenoma was demonstrated by MRI carried out at the end of treatment. Our findings lead to the following conclusions: a) administration of depot injections of bromocriptine to patients with CD appears unable to correct hypercortisolism, although it can induce restoration of menses in amenorrheic patients; b) enhanced PRL concentrations at the pituitary level are probably involved in the amenorrhea often accompanying Cushing's disease.