HYPERPROLACTINAEMIA AFTER EXTERNAL IRRADIATION FOR ACROMEGALY

Abstract
SUMMARY: The progress of twelve patients who received external irradiation of the pituitary as sole treatment for acromegaly was reviewed. In all cases a fall in serum GH was achieved and no patient developed hypopituitarism. Three had mild hyperprolactinaemia before therapy. In all twelve cases, PRL levels rose after treatment, in five entering the hyperprolactinaemic range. It is suggested that the most likely cause is interference with the supply of prolactin release inhibiting factor (PIF) by the effects of irradiation on the hypothalamus.