CLINICAL EVALUATION OF THE LUTEINIZING HORMONE-RELEASING HORMONE (LH-RH) TEST IN CASES WITH ANATOMICALLY VERIFIED DISORDERS OF THE HYPOTHALAMO-PITUITARY REGION

The effect of slow intravenous infusion of luteinizing hormone-releasing hormone (LH-RH) on serum LH was studied in 58 patients with anatomically verified hypothalamo-pituitary disorders as well as in control groups. Normal responses to the LH-RH test were found in 15 out of 15 cases with intrasellar pituitary tumours and in five out of six cases after transsphenoidal surgery for an intrasellar pituitary tumour. Twenty-one out of 25 patients where a pituitary tumour with both supra- and intrasellar extension had been removed had pathological responses to the test. All eight patients with hypothalamic disorders, mainly tumours not directly influencing the pituitary, gave normal responses to the LH-RH tests. Out of four patients with hypothalamopituitary malformations a pathological response to the LH-RH infusion was found in three cases and a normal response in one case. The increase of serum LH after LH-RH infusion was pronounced and rather constant in males and post-menopausal women. It was more difficult to evaluate a “normal” test response in women of fertile ages because of the great variations during the different menstrual phases. It is concluded that the LH-RH test may be of importance in the investigation of patients with suspected tumours of the pituitary as well as for differential diagnosis between hypothalamic and pituitary disorders of gonadotropin secretion.