Prolactin studies in "functionless" pituitary tumours.

Hyperprolactinaemia was found in all 17 women and in one out of six men who presented with hypogonadism and a radiologically enlarged sella turcica but no other clinical endocrine dysfunction. Some of the women also had galactorrhoea. The greater the level of hyperprolactinaemia in these 18 patients the larger their sellae turcica except in two patients with unusual features. The sella turcica was usually asymmetrically enlarged and there was rearly an upward extension of tumour, though the sella floor often showed some erosion on tomography. An oral dose of bromocriptine suppressed the hyperprolactinaemia in mose patients at the same rate as in normal post-partum women. Nine of the 18 patients with hyperprolactinaemia had low basal luteinizing hormone (LH) levels. The LH responsiveness to 100 mug of LH-releasing hormone (LHRH) was tested in 12, and eight showed subnormal values. Of eight biopsy specimens obtained four showed acidophil granules on light microscopy, and in five granules of various sizes were seen on electron microscopy.