HYPERPROLACTINEMIA IN PATIENTS WITH PITUITARY-ADENOMAS - THE PITUITARY-STALK COMPRESSION SYNDROME

Hyperprolactinaemia, unexplained by prolactin-production of the tumour is occasionally found in patients with pituitary tumours. This second ary hyperprolactinaemia has been ascribed to a mass effect of the tumo ur upon the pituitary stalk, obstructing the normal inhibitory hypotha lamic influence on the prolactin producing cells. In this study the ad enoma volume, amount of suprasellar enlargement of the tumour and the intrasellar pressure were measured in 42 patients operated upon consec utively for pituitary rumours. Secondary hyperprolactinaemia was found in six (14%). There was no difference as regards adenoma volume, amou nt of suprasellar extension or intrasellar pressure between the group of patients with elevated p-prolactin versus the group with normal p-p rolactin. We conclude that mechanisms other than pituitary stalk compr ession must be considered as the cause of secondary hyperprolactinaemi a.