Role of Melatonin in the Mechanisms Underlying Neuroendocrine Control of the Hypothalamo-Hypophyseal-Thyroid Axis

AbstractThyroid hormone (TH) regulation is important for development, energy homeostasis, heart function, and bone formation. To control the effects of TH in target organs, the hypothalamus-pituitary-thyroid (HPT) axis and the tissue-specific availability of TH are highly regulated by negative feedback. To exert a central feedback, TH must enter the brain via specific transport mechanisms and cross the blood-brain barrier. Here, tanycytes, which are located in the ventral walls of the 3rd ventricle in the mediobasal hypothalamus (MBH), function as gatekeepers. Tanycytes are able to transport, sense, and modify the release of hormones of the HPT axis and are involved in feedback regulation. In this review, we focus on the relevance of tanycytes in thyrotropin-releasing hormone (TRH) release and review available genetic tools to investigate the physiological functions of these cells.

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Role of fibroblast growth factor (FGF) signaling in the neuroendocrine control of human reproduction

Molecular and Cellular Endocrinology ◽

10.1016/j.mce.2011.05.042 ◽

2011 ◽

Vol 346 (1-2) ◽

pp. 37-43 ◽

Cited By ~ 15

Author(s):

Hichem Miraoui ◽

Andrew Dwyer ◽

Nelly Pitteloud

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Human Reproduction ◽

Fibroblast Growth ◽

Fgf Signaling ◽

Neuroendocrine Control

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Neuroendocrine Control of the Thymic Microenvironment: Role of Pituitary Hormones

Advances in Psychoneuroimmunology ◽

10.1007/978-1-4757-9104-4_5 ◽

1994 ◽

pp. 75-82

Author(s):

Wilson Savino ◽

Valeria Mello-Coelho ◽

Mireille Dardenne

Keyword(s):

Pituitary Hormones ◽

Neuroendocrine Control

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The Hypothalamic-Pituitary Thyroid Axis : Studies on the Regulatory Role of Thyrotropin Releasing Hormone (TRH)

Folia Endocrinologica Japonica ◽

10.1507/endocrine1927.52.9_908 ◽

1976 ◽

Vol 52 (9) ◽

pp. 908-925

Author(s):

Yoshifumi HIROOKA

Keyword(s):

Thyrotropin Releasing Hormone ◽

Regulatory Role ◽

Releasing Hormone ◽

Pituitary Thyroid Axis ◽

Thyroid Axis

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The Role of the Thyroid Axis in Fish

Frontiers in Endocrinology ◽

10.3389/fendo.2020.596585 ◽

2020 ◽

Vol 11 ◽

Author(s):

Cole K. Deal ◽

Helene Volkoff

Keyword(s):

Thyroid Axis

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Dominant Role of Thyrotropin-releasing Hormone in the Hypothalamic-Pituitary-Thyroid Axis

Journal of Biological Chemistry ◽

10.1074/jbc.m511530200 ◽

2005 ◽

Vol 281 (8) ◽

pp. 5000-5007 ◽

Cited By ~ 67

Author(s):

Amisra A. Nikrodhanond ◽

Tania M. Ortiga-Carvalho ◽

Nobuyuki Shibusawa ◽

Koshi Hashimoto ◽

Xiao Hui Liao ◽

...

Keyword(s):

Dominant Role ◽

Thyrotropin Releasing Hormone ◽

Releasing Hormone ◽

Pituitary Thyroid Axis ◽

Thyroid Axis

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The role of leptin in the regulation of TSH secretion in the fed state: in vivo and in vitro studies

Journal of Endocrinology ◽

10.1677/joe.0.1740121 ◽

2002 ◽

Vol 174 (1) ◽

pp. 121-125 ◽

Cited By ~ 78

Author(s):

TM Ortiga-Carvalho ◽

KJ Oliveira ◽

BA Soares ◽

CC Pazos-Moura

Keyword(s):

Fold Increase ◽

Adult Rats ◽

Fed State ◽

Rat Pituitary ◽

Pituitary Thyroid Axis ◽

Tsh Secretion ◽

Thyroid Axis

Leptin has been shown to stimulate the hypothalamus-pituitary-thyroid axis in fasting rodents; however, its role in thyroid axis regulation under physiological conditions is still under investigation. Here it was investigated in freely fed rats whether leptin modulates thyrotroph function in vivo and whether leptin has direct pituitary effects on TSH release. Since leptin is produced in the pituitary, the possibility was also investigated that leptin may be a local regulator of TSH release. TSH was measured by specific RIA. Freely fed adult rats 2 h after being injected with a single s.c. injection of 8 microg leptin/100 g body weight showed a 2-fold increase in serum TSH (P<0.05). Hemi-pituitary explants incubated with 10(-9) and 10(-7) M leptin for 2 h showed a reduced TSH release of 40 and 50% respectively (P<0.05). Conversely, incubation of hemi-pituitary explants with antiserum against leptin, aiming to block the action of locally produced leptin, resulted in higher TSH release (45%, P<0.05). In conclusion, also in the fed state, leptin has an acute stimulatory effect on TSH release in vivo, acting probably at the hypothalamus. However, the direct pituitary effect of leptin is inhibitory and data also provide evidence that in the rat pituitary leptin may act as an autocrine/paracrine inhibitor of TSH release.

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