HYPOTHALAMIC-PITUITARY-ADRENAL FUNCTION IN PATIENTS WITH PITUITARY TUMOURS

Abstract

ABSTRACT Hypothalamic-pituitary-adrenal function was investigated in 43 patients with pituitary tumours (22 acromegalics and 21 chromophobe adenomas) and in 7 patients with craniopharyngiomas. The subjects were divided into two groups, according to the intrasellar or to the suprasellar spread of the tumour. Plasma and urinary 17-OHCS were evaluated in basal conditions and after the following tests: ACTH, metyrapone, dexamethasone, LVP, hypoglycaemia and pyrogen. Only in 10 subjects were all the tests normal, while there was a complete lack of response to the performed tests in 12 cases. Under basal conditions a reduced urinary 17-OHCS excretion was observed in 24% of the patients, while plasma 17-OHCS levels appeared to be decreased only in 10 % of patients. The adrenal reserve was reduced in 4 % of the cases. A greater frequency of negative responses (40 %) was shown by the metyrapone test. Dexamethasone administration failed to suppress plasma 17-OHCS in 29 % of the subjects. The LVP test demonstrated abnormal results in 42 % of the patients examined. The hypoglycaemia test caused the greatest percentage of impaired responses (58 %) and the pyrogen test gave a higher incidence of normal results. Our data suggest that the incidence of impaired tests is greater in patients with pituitary tumours with suprasellar spread which particularly tend to cause hypothalamic damage.