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Horm Metab Res 1974; 6(3): 190-195
DOI: 10.1055/s-0028-1093871
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© Georg Thieme Verlag KG Stuttgart · New York

Prolactin and Thyrotropin in Thyroid Diseases: Lack of Evidence for a Physiological Role of Thyrotropin-Releasing Hormone in the Regulation of Prolactin Secretion[*]

M.  L'Hermite1 , C.  Robyn1 [**] , J.  Golstein2 , G.  Rothenbuchner3 [***] , J.  Birk3 , U.  Loos3 , M.  Bonnyns4 , L.  Vanhaelst4
  • 1Human Reproduction Research Unit, Department of Gynecology and Obstretrics, Free University of Brussels, Belgium
  • 2Institute of Interdisciplinary Research in Human and Nuclear Biology, Free University of Brussels, Belgium
  • 3Department of Endocrinology and Metabolism, Center of Internal Medicine and Pediatrics University of Ulm, Germany
  • 4Department of Medicine and Laboratory of Experimental Medicine, Free Universities of Brussels, Belgium
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Publication History

Publication Date:
08 January 2009 (online)

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Abstract

The purpose of the present study was to investigate whether thyrotropin-releasing hormone (TRH) could play a role in the regulation of prolactin (PRL) secretion, and whether thyroid hormones would exert a feedback effect on the PRL response to TRH. Therefore, serum thyrotropin (TSH) and PRL levels were measured in basal conditions in patients with thyroid diseases, and after TRH stimulation in hyperthyroid patients and in normal subjects treated with triiodothyronine (T3). Mean basal PRL levels of the adults with asymptomatic thyroiditis (n = 10), with spontaneous myxoedema (n = 28), and with hyperthyroidism (n = 34) were not significantly different from that of normal euthyroid adults (n = 30). On the contrary, mean PRL levels of 6 children with congenital myxoedema (athyreosis) were significantly (p < 0.001) elevated. In 4 normal men, short-term (3 days) pretreatment with 100 µg T3 failed to inhibit the PRL response to synthetic TRH, whereas T3 inhibited the TSH response to TRH. The mean TRH-induced PRL response observed in 7 hyperthyroid women was lower than expected for normal euthyroid women. The lack of short-term effect of thyroid hormones on TRH-induced PRL release argues against their direct action on the lactotropes. Moreover, the present data do not favour the hypothesis of a physiological role of TRH in the regulation of PRL secretion, and suggest that it rather acts as a pharmacological PRL releaser.

Key words

TSH - TRH - T3 - Prolactin - Hypothyroidism - Hyperthyroidism - Asymptomatic Thyroidism - Athyreosis

1 Parts of these investigations were reported in abstracts (L'Hermite, Bonnyns, Golstein, Robyn and Vanhaelst 1972b. Vanhaelst, Golstein, Bonnyns, Robyn, Copinschi and L'Hermite 1973)

1 Parts of these investigations were reported in abstracts (L'Hermite, Bonnyns, Golstein, Robyn and Vanhaelst 1972b. Vanhaelst, Golstein, Bonnyns, Robyn, Copinschi and L'Hermite 1973)

2 Chercheur qualifié au Fonds National de la Recherche Scientifique (Belgium)

3 Supported by Deutsche Forschungsgemeinschaft, Bad Godesberg, SFB 87, Endocrinologie, Ulm

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