Since surgical therapy of large prolactin-secreting pituitary tumours normalises serum prolactin levels or gonadal function in less than twenty per cent of patients, particularly those with high prolactin levels, there is a need for another approach to the problem. Three major lines of evidence suggest that medical therapy may help in the treatment of these large tumours:
ΓÇó Visual field defects due to prolactinomas pressing on the optic chiasm have improved with bromocriptine therapy alone.
ΓÇó Dopamine agonist therapy has been shown, by neuroradiologic evaluations, to reduce the size of prolactinomas.
ΓÇó Bromocriptine reduces DNA turnover and the mitotic index in the in situ pituitary of the rat.
