Chronobiology of the Hypothalamic-Pituitary-Thyroid Axis

Nicolau, G Y; Haus, Erhard

doi:10.1007/978-3-642-78734-8_24

Cited by 13 publications

(15 citation statements)

References 106 publications

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“…Using previous TSH assays, a seasonal 'variation' has been reported in basal plamsa TSH concentrations in prepubertal children, women, patients with primary hypothyroidism replaced on T4, and in young men (Halberg et al, 1981;Konno & Morikawa, 1982;Sensi et al, 1983;Bellastella et al, 1984). (ii) Some investigators found a seasonal variation in serum or plasma thyroid hormones (Smals et al, 1977;Halberg et al, 1981;Harrop et al, 1985;Haus et al, 1988;Nicolau & Haus, 1992). T3 and T4 serum/plasma concentrations were highest from September to February (Harrop et al, 1985).…”

mentioning

confidence: 99%

Components of biological variation, including seasonality, in blood concentrations of TSH, TT3, FT4, PRL, cortisol and testosterone in healthy volunteers

Maes

Mommen

Hendrickx

et al. 1997

Clinical Endocrinology

203

120

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mentioning

confidence: 99%

Components of biological variation, including seasonality, in blood concentrations of TSH, TT3, FT4, PRL, cortisol and testosterone in healthy volunteers

Maes

Mommen

Hendrickx

et al. 1997

Clinical Endocrinology

203

120

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“…In the placebo‐treated women, endogenous levels of MEL in the group with high MEL seem to affect thyroid function positively. The interpretation of this placebo‐dependent change could also be attributed, in the high MEL group, to the physiological changes of thyroid function in relation to temperature and season 21,22. It is thus clear that low MEL levels can be suggestive of low thyroid function and that administration of MEL may prevent and cure the decline of thyroid function in perimenopausal women.…”

Section: Discussionmentioning

confidence: 96%

“…The most important and largely unexpected finding was the clear‐cut effect of MEL on thyroid function (see Table 2). Our trial was initiated in late summer and was concluded in late winter, a season when physiological levels of thyroid hormones are higher 21. In spite of the obvious variability of T3 and T4 values, when the effect of MEL was evaluated in relation to the basal levels of MEL in the saliva it can be seen that MEL produced a significant increase of T3 and T4 in the low and medium MEL groups, but only T3 increased in the high MEL group.…”

Section: Discussionmentioning

confidence: 99%

“…The interpretation of this placebo-dependent change could also be attributed, in the high MEL group, to the physiological changes of thyroid function in relation to temperature and season. 21,22 It is thus clear that low MEL levels can be suggestive of low thyroid function and that administration of MEL may prevent and cure the decline of thyroid function in perimenopausal women. Our findings are confirmed by the positive correlation existing between basal levels of MEL and T3 at time 0 in all women.…”

Section: Discussionmentioning

confidence: 99%

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Effects of Melatonin in Perimenopausal and Menopausal Women: Our Personal Experience

Bellipanni

2005

Annals of the New York Academy of Sciences

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The purpose of this clinical trial on possible effects of nocturnal MEL administration in perimenopausal women was to find if MEL by itself modifies levels of hormones and produces changes of any kind, independently of age (42-62 years of age) and the stage of the menstrual cycle. It is accepted that a close link exists between the pineal gland, MEL, and human reproduction and that a relationship exists between adenohypophyseal and steroid hormones and MEL during the ovarian cycle, perimenopause, and menopause. Subjects took a daily dose of 3 mg synthetic melatonin or a placebo for 6 months. Levels of melatonin were determined from five daily saliva samples taken at fixed times. Hormone levels were determined from blood samples three times over the 6-month period. Our results indicate that a cause-effect relationship between the decline of nocturnal levels of MEL and onset of menopause may exist. The follow up controls show that MEL abrogates hormonal, menopause-related neurovegetative disturbances and restores menstrual cyclicity and fertility in perimenopausal or menopausal women. At present we assert that the six-month treatment with MEL produced a remarkable and highly significant improvement of thyroid function, positive changes of gonadotropins towards more juvenile levels, and abrogation of menopause-related depression.

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“…However, it remains unclear why TSH does not stimulate thymocyte proliferation in the evening. Both TRH and TSH exhibit circadian variations of secretion in man and in rats [16]. Although the data on circadian variations of TRH and TSH receptors are lacking, such circadian variations seem very likely.…”

Section: Discussionmentioning

confidence: 99%

Time of Day-Dependent Effects of Thyroliberin and Thyrotropin on Thymocyte Proliferation in Rats

Winczyk

Pawlikowski

2000

Neuroimmunomodulation

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Our earlier studies have shown that thyroliberin (TRH) as well as thyrotropin (TSH) enhanced thymus cell proliferation. The aim of the present study was to investigate whether the effects of TRH and TSH on thymocyte proliferation depend on time of day. A single subcutaneous injection of TRH (25 μg/animal) or TSH (3 IU/animal) was made at 9:00 h (1 h after light onset) or at 18:00 h (10 h after light onset) in 3-month-old male Wistar rats. The animals were killed 24 h later. The proliferation of thymocytes was assessed by incorporation of bromodeoxyuridine into cell nuclei. Thymocyte proliferation was significantly increased by TSH administration at 9:00 h, whereas treatment given at 18:00 h was ineffective. TRH enhanced the proliferation when injected at 9:00 h, but had an inhibitory effect when administered at 18:00 h. These data indicate that the effects of TRH and TSH on thymocyte proliferation are dependent on time of day.

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Chronobiology of the Hypothalamic-Pituitary-Thyroid Axis

Cited by 13 publications

References 106 publications

Components of biological variation, including seasonality, in blood concentrations of TSH, TT3, FT4, PRL, cortisol and testosterone in healthy volunteers

Components of biological variation, including seasonality, in blood concentrations of TSH, TT3, FT4, PRL, cortisol and testosterone in healthy volunteers

Effects of Melatonin in Perimenopausal and Menopausal Women: Our Personal Experience

Time of Day-Dependent Effects of Thyroliberin and Thyrotropin on Thymocyte Proliferation in Rats

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