THYROTROPHIN RESPONSES TO INTRAVENOUS THYROTROPHIN‐RELEASING HORMONE IN PATIENTS WITH HYPOTHALAMIC AND PITUITARY DISEASE

Plasma immunoreactive thyrotrophin (TSH) responses to synthetic thyrotrophin releasing hormone (TRH) have been measured in forty‐five patients with pituitary or hypothalamic disease (largely non‐functioning and functioning pituitary tumours) tested before and/or after ablative treatment. Subnormal TSH responses usually indicated impaired pituitary function but were less sensitive indices than those of human growth hormone (HGH) after hypoglycaemia. High basal TSH values with exaggerated rises after TRH were occasionally found with hypothyroidism and impaired HGH and cortisol secretion. Delayed TSH responses were indicative of hypothalamic disease in some cases, but in others were associated with pituitary tumours without overt hypothalamic disease. Normal TRH tests were found with hypothyroidism, while five abnormal tests (four delayed) were found in euthyroid patients. Patterns of TSH response to TRH in hypothalamic‐pituitary disease are complex and their significance is not always clear. Copyright © 1974, Wiley Blackwell. All rights reserved