Triiodothyronine and Thyrotropin-Releasing Hormone Interaction on TSH Release in Man

Abstract

In order to study thyrotropin releasing hormone (TRH)-thyroid hormone interaction, we examined thyrotropin (TSH) behaviour after synthetic TRH administration in 24 euthyroid subjects, 3 patients with primary hypothyroidism and 10 hyper thyroids. 8 normal subjects were studied before and after triiodothyronine (T₃) treatment with increasíng TRH dosage. Our results suggest that (1) TRH-thyroid hormone interaction is dose-related: this means that TSH response to TRH depends on both thyroid hormone and TRH concentration; (2) T₃-TRH interaction on TSH release is only roughly quantitative since it is suggested that other extrathyroidal factors interfere with this mechanism controlling TSH secretion.

Serum levels of thyroid hormones and thyroid stimulating hormone in patients with biliogenic and hyperlipidaemic acute pancreatitis: Difference and value in predicting disease severity

“…25 Circulating T3/T4 can feed back to the hypothalamus and anterior pituitary gland to negatively regulate thyrotropin releasing hormone (TRH) and TSH release. 39 However, serum levels of TSH were also significantly decreased in the MSAP group compared with MAP group in the present study, despite the decline in FT3 levels. Since TSH levels are regulated dually by THs and TRH, the decline of TSH may be caused by the impact of endotoxins and cytokines on the hypothalamus and pituitary gland or the altered response of the pituitary gland to THs.…”

The relationship between anorexia nervosa and depression: A reevaluation

“…Such homeostatic pituitary regulation is not known to occur in depression alone. Indeed, low levels of circulating thyroid hormone as may occur in depression (Gold, Pottash, Mueller, & Extein, 1981) or primary hypothyroidism (Vigneri, Papalia, Pezzino, Squatrito, Motto, & Polosa, 1972) predictably lead to an augmented TSH response rather than the blunted or delayed response seen in AN.…”