Tumour volume changes (expressed as a percentage of the pretreatment volume) during bromocriptine therapy in seven patients with macroprolactinomas (left-hand panel) and eight patients with non-functioning tumours, several of whom had ‘disconnection’ hyperprolactinaemia (right-hand panel). Note that all of the prolactinomas shrank, by an average of approximately 50%, and that most shrinkage took place during the first 3 months of treatment. None of the nonfunctioning tumours shrank. (With permission from Bevan JS, Adams CB, Burke CW, Morton KE, Molyneux AJ, Moore RA, et al. Factors in the outcome of transsphenoidal surgery for prolactinoma and non-functioning pituitary tumour, including pre-operative bromocriptine therapy. Clin Endocrinol, 1987; 26: 541–56).