Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock

Research output: Contribution to journalJournal articlepeer-review

Standard

Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock. / Fahrenkrug, J.; Georg, B.; Hannibal, J.; Jørgensen, H. L.

In: Journal of Endocrinology, Vol. 233, No. 3, 06.2017, p. 209-216.

Research output: Contribution to journalJournal articlepeer-review

Harvard

Fahrenkrug, J, Georg, B, Hannibal, J & Jørgensen, HL 2017, 'Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock', Journal of Endocrinology, vol. 233, no. 3, pp. 209-216. https://doi.org/10.1530/JOE-17-0111

APA

Fahrenkrug, J., Georg, B., Hannibal, J., & Jørgensen, H. L. (2017). Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock. Journal of Endocrinology, 233(3), 209-216. https://doi.org/10.1530/JOE-17-0111

Vancouver

Fahrenkrug J, Georg B, Hannibal J, Jørgensen HL. Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock. Journal of Endocrinology. 2017 Jun;233(3):209-216. https://doi.org/10.1530/JOE-17-0111

Author

Fahrenkrug, J. ; Georg, B. ; Hannibal, J. ; Jørgensen, H. L. / Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock. In: Journal of Endocrinology. 2017 ; Vol. 233, No. 3. pp. 209-216.

Bibtex

@article{8ac4d1880321498dac34692194af6cb3,
title = "Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock",
abstract = "The endocrine body rhythms including the hypothalamic-pituitary-thyroid axis seem to be regulated by the circadian timing system, and daily rhythmicity of circulating thyroid-stimulating hormone (TSH) is well established. The circadian rhythms are generated by endogenous clocks in the central brain oscillator located in the hypothalamic suprachiasmatic nucleus (SCN) as well as multiple peripheral clocks, but information on the existence and function of a thyroid clock is limited. The molecular machinery in all clock cells is composed of a number of clock genes and their gene products are connected by autoregulatory feedback loops. Here, we provide evidence for a thyroid clock in the rat by demonstrating 24-h antiphase oscillations for the mRNA of the canonical clock genes Per1 and Bmal1, which was unaffected by hypophysectomy. By immunostaining, we supported the existence of a core oscillator in the individual thyroid cells by demonstrating a daily cytoplasmatic-nuclear shuttling of PER1 protein. In normal rats, we found a significant daily rhythmicity in the circulating thyroid hormones preceded by a peak in TSH. In hypophysectomised rats, although the thyroid clock was not affected, the oscillations in circulating thyroid hormones were abolished and the levels were markedly lowered. No daily oscillations in the expression of TSH receptor mRNA were observed in neither control rats nor hypophysectomised rats. Our findings indicate that the daily rhythm of thyroid hormone secretion is governed by SCN signalling via the rhythmic TSH secretion rather than by the local thyroid clock, which was still ticking after hypophysectomy.",
keywords = "Circadian rhythms, Clock genes, HPT axis, Pituitary, Thyroid hormones",
author = "J. Fahrenkrug and B. Georg and J. Hannibal and J{\o}rgensen, {H. L.}",
year = "2017",
month = jun,
doi = "10.1530/JOE-17-0111",
language = "English",
volume = "233",
pages = "209--216",
journal = "Journal of Endocrinology",
issn = "0022-0795",
publisher = "BioScientifica Ltd.",
number = "3",

}

RIS

TY - JOUR

T1 - Hypophysectomy abolishes rhythms in rat thyroid hormones but not in the thyroid clock

AU - Fahrenkrug, J.

AU - Georg, B.

AU - Hannibal, J.

AU - Jørgensen, H. L.

PY - 2017/6

Y1 - 2017/6

N2 - The endocrine body rhythms including the hypothalamic-pituitary-thyroid axis seem to be regulated by the circadian timing system, and daily rhythmicity of circulating thyroid-stimulating hormone (TSH) is well established. The circadian rhythms are generated by endogenous clocks in the central brain oscillator located in the hypothalamic suprachiasmatic nucleus (SCN) as well as multiple peripheral clocks, but information on the existence and function of a thyroid clock is limited. The molecular machinery in all clock cells is composed of a number of clock genes and their gene products are connected by autoregulatory feedback loops. Here, we provide evidence for a thyroid clock in the rat by demonstrating 24-h antiphase oscillations for the mRNA of the canonical clock genes Per1 and Bmal1, which was unaffected by hypophysectomy. By immunostaining, we supported the existence of a core oscillator in the individual thyroid cells by demonstrating a daily cytoplasmatic-nuclear shuttling of PER1 protein. In normal rats, we found a significant daily rhythmicity in the circulating thyroid hormones preceded by a peak in TSH. In hypophysectomised rats, although the thyroid clock was not affected, the oscillations in circulating thyroid hormones were abolished and the levels were markedly lowered. No daily oscillations in the expression of TSH receptor mRNA were observed in neither control rats nor hypophysectomised rats. Our findings indicate that the daily rhythm of thyroid hormone secretion is governed by SCN signalling via the rhythmic TSH secretion rather than by the local thyroid clock, which was still ticking after hypophysectomy.

AB - The endocrine body rhythms including the hypothalamic-pituitary-thyroid axis seem to be regulated by the circadian timing system, and daily rhythmicity of circulating thyroid-stimulating hormone (TSH) is well established. The circadian rhythms are generated by endogenous clocks in the central brain oscillator located in the hypothalamic suprachiasmatic nucleus (SCN) as well as multiple peripheral clocks, but information on the existence and function of a thyroid clock is limited. The molecular machinery in all clock cells is composed of a number of clock genes and their gene products are connected by autoregulatory feedback loops. Here, we provide evidence for a thyroid clock in the rat by demonstrating 24-h antiphase oscillations for the mRNA of the canonical clock genes Per1 and Bmal1, which was unaffected by hypophysectomy. By immunostaining, we supported the existence of a core oscillator in the individual thyroid cells by demonstrating a daily cytoplasmatic-nuclear shuttling of PER1 protein. In normal rats, we found a significant daily rhythmicity in the circulating thyroid hormones preceded by a peak in TSH. In hypophysectomised rats, although the thyroid clock was not affected, the oscillations in circulating thyroid hormones were abolished and the levels were markedly lowered. No daily oscillations in the expression of TSH receptor mRNA were observed in neither control rats nor hypophysectomised rats. Our findings indicate that the daily rhythm of thyroid hormone secretion is governed by SCN signalling via the rhythmic TSH secretion rather than by the local thyroid clock, which was still ticking after hypophysectomy.

KW - Circadian rhythms

KW - Clock genes

KW - HPT axis

KW - Pituitary

KW - Thyroid hormones

U2 - 10.1530/JOE-17-0111

DO - 10.1530/JOE-17-0111

M3 - Journal article

C2 - 28348112

AN - SCOPUS:85020005530

VL - 233

SP - 209

EP - 216

JO - Journal of Endocrinology

JF - Journal of Endocrinology

SN - 0022-0795

IS - 3

ER -

ID: 196882871