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THE EFFECTS OF A SYNTHETIC THYROTROPHIN RELEASING HORMONE (TRH) IN NORMAL AND ENDOCRINOPATHIC SUBJECTS

1972; Oxford University Press; Volume: 71; Issue: 2 Linguagem: Inglês

10.1530/acta.0.0710209

1479-683X

G. Faglia, P. Beck‐Peccoz, B. Ambrosi, Carlo Ferrari, P. Travaglini,

Thyroid Cancer Diagnosis and Treatment

ABSTRACT The effects of thyrotrophin releasing hormone (TRH) on plasma thyrotrophin (HTSH), thyroxine iodine (T 4 -I), growth hormone (HGH) and cortisol were studied in healthy and endocrinopathic subjects. In normal subjects rapid iv injection of 100, 200, 400, 600, 800 μg of TRH caused definite increases in plasma HTSH with a dose-response correlation between 100 and 200 μg; the peak occurred at 20–30 min at any dose level; iv infusion of 1000 μg over 30 min was followed by highly variable rises in plasma HTSH; the oral administration of 20 mg caused a definite and prolonged increase. In endocrinopathic subjects a standard dose of 600 μg of TRH was rapidly iv injected: 5 euthyroid patients with high 131 I thyroidal uptake showed a normal increase in HTSH; 10 cases of Graves' disease, 5 of hyperactive adenomas as well as 4 normal subjects pre-treated with triiodothyronine showed no response; out of 5 cases of Graves' disease re-investigated after remission 3 showed no response, while 2 had an exaggerated response; 5 cases of primary myxoedema showed a very marked and prolonged response; out of 2 patients with idiopathic secondary hypothyroidism 1 did not respond at all and 1 showed a large and prolonged increase with a late peak; out of 4 cases of secondary hypothyroidism due to pituitary tumours, 2 gave normal responses, 1 showed a very marked and prolonged rise and 1 had a poor response; the same subject, after selective adenomectomy, however, had an exaggerated response; 12 euthyroid patients with pituitary tumours were examined: 3 did not respond at all, 4 had a normal increase in plasma HTSH and 5 gave a prolonged and exaggerated response. The serum T 4 -I showed an upward trend after TRH iv; however, the increase was not present in all instances. After oral administration of TRH a more definite increase was reached. It was demonstrated that TRH does not promote the release of HGH and ACTH.