scholarly journals Progesterone regulates hypothalamic-pituitary-thyroid axis

2017 ◽  
Author(s):  
Chunyun Zhong ◽  
Kewen Xiong ◽  
Xin Wang
Keyword(s):  
Thyroid Hormone ◽  
Aquatic Ecosystems ◽  
Endocrine System ◽  
Hormone Metabolism ◽  
Hormone Synthesis ◽  
Thyroid Hormone Metabolism ◽  
Expression Of Genes ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Hpt Axis

AbstractProgesterone is a natural steroid hormone excreted by animals and humans, which has been frequently detected in the aquatic ecosystems. The effects of the residual progesterone on fish are unclear. In this study, we aimed to examine the effects of progesterone on the hypothalamic-pituitary-thyroid (HPT) axis by detecting the gene transcriptional expression levels. Zebrafish embryos were treated with different concentrations of progesterone from 12 hours post-fertilization (hpf) to 120 hpf. Total mRNA was extracted and the transcriptional profiles of genes involved in HPT axis were examined using qPCR. The genes related to thyroid hormone metabolism and thyroid hormone synthesis were up-regulated in zebrafish exposed to progesterone. These results indicated that progesterone affected the mRNA expression of genes involved in the HPT axis, which might interrupt the endocrine system in zebrafish. Our data also suggested that zebrafish is a useful tool for evaluating the effects of chemicals on the thyroid endocrine system.

scholarly journals Simultaneous changes in central and peripheral components of the hypothalamus-pituitary-thyroid axis in lipopolysaccharide-induced acute illness in mice

2004 ◽  
Vol 182 (2) ◽  
pp. 315-323 ◽  
Author(s):  
A Boelen ◽  
J Kwakkel ◽  
DC Thijssen-Timmer ◽  
A Alkemade ◽  
E Fliers ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mrna Expression ◽  
Time Course ◽  
Acute Illness ◽  
Hormone Metabolism ◽  
Thyroid Hormone Metabolism ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Hpt Axis

During illness, major changes in thyroid hormone metabolism and regulation occur; these are collectively known as non-thyroidal illness and are characterized by decreased serum triiodothyronine (T(3)) and thyroxine (T(4)) without an increase in serum TSH. Whether alterations in the central part of the hypothalamus-pituitary-thyroid (HPT) axis precede changes in peripheral thyroid hormone metabolism instead of vice versa, or occur simultaneously, is presently unknown. We therefore studied the time-course of changes in thyroid hormone metabolism in the HPT axis of mice during acute illness induced by bacterial endotoxin (lipopolysaccharide; LPS).LPS rapidly induced interleukin-1beta mRNA expression in the hypothalamus, pituitary, thyroid and liver. This was followed by almost simultaneous changes in the pituitary (decreased expression of thyroid receptor (TR)-beta2, TSHbeta and 5'-deiodinase (D1) mRNAs), the thyroid (decreased TSH receptor mRNA) and the liver (decreased TRbeta1 and D1 mRNA). In the hypothalamus, type 2 deiodinase mRNA expression was strongly increased whereas preproTRH mRNA expression did not change after LPS. Serum T(3) and T(4) fell only after 24 h.Our results suggested almost simultaneous involvement of the whole HPT axis in the downregulation of thyroid hormone metabolism during acute illness.

scholarly journals Disruption of thyroid endocrine in zebrafish exposed to BDE-209

2017 ◽  
Author(s):  
Dong Li ◽  
Xin Wang
Keyword(s):  
Mrna Expression ◽  
Polybrominated Diphenyl Ethers ◽  
Endocrine System ◽  
Potential Effect ◽  
Thyroid Stimulating Hormone ◽  
Expression Of Genes ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Hpt Axis ◽  
Bde 209

AbstractPolybrominated diphenyl ethers (PBDs) could adversely affect the thyroid endocrine system; previous studies report that BDE-209 has the potential effect on the fish thyroid endocrine system. In this study, we aimed to verify the bioconcentration and metabolism of BDE-209 in zebrafish. One day post-fertilization (dpf) zebrafish embryos were treated with different concentrations of BDE-209 (0, 0.01, 0.1 and 1 mg/L) until 10 dpf. BDE-209 was obviously accumulated in the zebrafish after 10 days exposure, and the metabolic products such as octa-BDE and nona-BDE were detected. After treated with BDE-209, the triiodthyronine (T3) and thyroxine (T4) levels were significantly decreased, suggesting that exposure to BDE-209 could disrupt the thyroid endocrine system in zebrafish. The transcriptional expression of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis was altered. The mRNA expression levels of corticotrophin-releasing hormone (CRH) and thyroid-stimulating hormone (TSHβ) were significantly increased. The mRNA expression of pax8 and nkx2.1 which regulate thyroid development and synthesis were also increased. These data indicated that BDE-209 could disrupt the thyroid endocrine system in zebrafish, which could be assessed by hypothalamic-pituitary-thyroid axis.

scholarly journals Interleukin-18, a proinflammatory cytokine, contributes to the pathogenesis of non-thyroidal illness mainly via the central part of the hypothalamus-pituitary-thyroid axis

2004 ◽  
pp. 497-502 ◽  
Author(s):  
A Boelen ◽  
J Kwakkel ◽  
M Platvoet-ter Schiphorst ◽  
B Mentrup ◽  
A Baur ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mrna Expression ◽  
Proinflammatory Cytokine ◽  
Biological Properties ◽  
Thyroid Hormone Metabolism ◽  
Pituitary Thyroid Axis ◽  
Serum T3 ◽  
Thyroid Axis ◽  
Hpt Axis

OBJECTIVE: Proinflammatory cytokines are involved in the pathogenesis of non-thyroidal illness (NTI), as shown by studies with IL-6-/- and IL-12-/- mice. Interleukin (IL)-6 changes peripheral thyroid hormone metabolism, and IL-12 seems to be involved in the regulation of the central part of the hypothalamic-pituitary-thyroid (HPT) axis during illness. IL-18 is a proinflammatory cytokine which shares important biological properties with IL-12, such as interferon (IFN)-gamma-inducing activity. DESIGN: By studying the changes in the HPT-axis during bacterial lipopolysaccharide (LPS)-induced illness in IL-18-/-, IFNgammaR-/- and wild-type (WT) mice, we wanted to unravel the putative role of IL-18 and IFNgamma in the pathogenesis of NTI. RESULTS: LPS induced a decrease in pituitary type 1 deiodinase (D1) activity (P<0.05, ANOVA) in WT mice, but not in IL-18-/- mice, while the decrease in D2 activity was similar in both strains. LPS decreased serum thyroid hormone levels and liver D1 mRNA within 24 h similarly in IL-18-/-, and WT mice. The expression of IL-1, IL-6 and IFNgamma mRNA expression was significantly lower in IL-18-/- mice than in WT, while IL-12 mRNA expression was similar. IFNgammaR-/- mice had higher basal D1 activity in the pituitary than WT mice (P<0.05); LPS induced a decrease of D2, but not of D1, activity in the pituitary which was similar in both strains. In the liver, the LPS-induced increase in cytokine expression was not different between IFNgammaR-/- mice and WT mice, and the decrease in serum T3 and T4 levels and hepatic D1 mRNA was also similar. CONCLUSIONS: The relative decrease in serum T3 and T4 and liver D1 mRNA in response to LPS is similar in IL-18-/-, IFNgammaR-/- and WT mice despite significant changes in hepatic cytokine induction. However, the LPS-induced decrease in D1 activity in the pituitary of WT mice is absent in IL-18-/- mice; in contrast, LPS did not decrease pituitary D1 activity in the IFNgammaR-/- mice or their WT, which might be due to the genetic background of the mice. Our results suggest that IL-18 is also involved in the regulation of the central part of the HPT axis during illness.

scholarly journals Chronic local inflammation in mice results in decreased TRH and type 3 deiodinase mRNA expression in the hypothalamic paraventricular nucleus independently of diminished food intake

2006 ◽  
Vol 191 (3) ◽  
pp. 707-714 ◽  
Author(s):  
A Boelen ◽  
J Kwakkel ◽  
W M Wiersinga ◽  
E Fliers
Keyword(s):  
Thyroid Hormone ◽  
Food Intake ◽  
Mrna Expression ◽  
Chronic Inflammation ◽  
Paraventricular Nucleus ◽  
Local Inflammation ◽  
Hormone Metabolism ◽  
Thyroid Hormone Metabolism ◽  
Pituitary Thyroid Axis ◽  
Hpt Axis

During illness, changes in thyroid hormone metabolism occur, known as nonthyroidal illness and characterised by decreased serum triiodothyronine (T3) and thyroxine (T4) without an increase in TSH. A mouse model of chronic illness is local inflammation, induced by a turpentine injection in each hind limb. Although serum T3 and T4 are markedly decreased in this model, it is unknown whether turpentine administration affects the central part of the hypothalamus–pituitary–thyroid axis (HPT-axis). We therefore studied thyroid hormone metabolism in hypothalamus and pituitary of mice during chronic inflammation induced by turpentine injection. Using pair-fed controls, we could differentiate between the effects of chronic inflammation per se and the effects of restricted food intake as a result of illness. Chronic inflammation increased interleukin (IL)-1β mRNA expression in the hypothalamus more rapidly than in the pituitary. This hypothalamic cytokine response was associated with a rapid increase in local D2 mRNA expression. By contrast, no changes were present in pituitary D2 expression. TSHβ mRNA expression was altered compared with controls. Comparing chronic inflamed mice with pair-fed controls, both preproTSH releasing hormone (TRH) and D3 mRNA expression in the paraventricular nucleus were significantly lower 48 h after turpentine administration. The timecourse of TSHβ mRNA expression was completely different in inflamed mice compared with pair-fed mice. Turpentine administration resulted in significantly decreased TSHβ mRNA expression only after 24 h while later in time it was lower in pair-fed controls. In conclusion, central thyroid hormone metabolism is altered during chronic inflammation and this cannot solely be attributed to diminished food intake.

scholarly journals Neuropeptide Y1 and Y5 Receptors Mediate the Effects of Neuropeptide Y on the Hypothalamic-Pituitary-Thyroid Axis

Endocrinology ◽  
2002 ◽  
Vol 143 (12) ◽  
pp. 4513-4519 ◽  
Author(s):  
Csaba Fekete ◽  
Sumit Sarkar ◽  
William M. Rand ◽  
John W. Harney ◽  
Charles H. Emerson ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Receptor Agonist ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Ad Libitum ◽  
Thyroid Hormone Levels ◽  
Hpt Axis

Abstract Neuropeptide Y (NPY) is one of the most important hypothalamic-derived neuropeptides mediating the effects of leptin on energy homeostasis. Central administration of NPY not only markedly stimulates food intake, but simultaneously inhibits the hypothalamic-pituitary-thyroid axis (HPT axis), replicating the central hypothyroid state associated with fasting. To identify the specific NPY receptor subtypes involved in the action of NPY on the HPT axis, we studied the effects of the highly selective Y1 ([Phe7,Pro34]pNPY) and Y5 ([chicken pancreatic polypeptide1–7, NPY19–23, Ala31, Aib32 (aminoisobutyric acid), Q34]human pancreatic polypeptide) receptor agonists on circulating thyroid hormone levels and proTRH mRNA in hypophysiotropic neurons of the hypothalamic paraventricular nucleus. The peptides were administered continuously by osmotic minipump into the cerebrospinal fluid (CSF) over 3 d in ad libitum-fed animals and animals pair-fed to artificial CSF (aCSF)-infused controls. Both Y1 and Y5 receptor agonists nearly doubled food intake compared with that of control animals receiving aCSF, similar to the effect observed for NPY. NPY, Y1, and Y5 receptor agonist administration suppressed circulating levels of thyroid hormones (T3 and T4) and resulted in inappropriately normal or low TSH levels. These alterations were also associated with significant suppression of proTRH mRNA in the paraventricular nucleus, particularly in the Y1 receptor agonist-infused group [aCSF, NPY, Y1, and Y5 (density units ± sem), 97.2 ± 8.6, 39.6 ± 8.4, 19.9 ± 1.9, and 44.6 ± 8.4]. No significant differences in thyroid hormone levels, TSH, or proTRH mRNA were observed between the agonist-infused FSanimals eating ad libitum and the agonist-infused animals pair-fed with vehicle-treated controls. These data confirm the importance of both Y1 and Y5 receptors in the NPY-mediated increase in food consumption and demonstrate that both Y1 and Y5 receptors can mediate the inhibitory effects of NPY on the HPT axis.

scholarly journals Minireview: The Neural Regulation of the Hypothalamic-Pituitary-Thyroid Axis

Endocrinology ◽  
2012 ◽  
Vol 153 (9) ◽  
pp. 4128-4135 ◽  
Author(s):  
Ricardo H. Costa-e-Sousa ◽  
Anthony N. Hollenberg
Keyword(s):  
Thyroid Hormone ◽  
Adult Life ◽  
Feedback System ◽  
Primary Hypothyroidism ◽  
Neural Regulation ◽  
Pituitary Thyroid Axis ◽  
Genes Encoding ◽  
Thyroid Axis ◽  
Hpt Axis

Thyroid hormone (TH) signaling plays an important role in development and adult life. Many organisms may have evolved under selective pressure of exogenous TH, suggesting that thyroid hormone signaling is phylogenetically older than the systems that regulate their synthesis. Therefore, the negative feedback system by TH itself was probably the first mechanism of regulation of circulating TH levels. In humans and other vertebrates, it is well known that TH negatively regulates its own production through central actions that modulate the hypothalamic-pituitary-thyroid (HPT) axis. Indeed, primary hypothyroidism leads to the up-regulation of the genes encoding many key players in the HPT axis, such as TRH, type 2 deiodinase (dio2), pyroglutamyl peptidase II (PPII), TRH receptor 1 (TRHR1), and the TSH α- and β-subunits. However, in many physiological circumstances, the activity of the HPT axis is not always a function of circulating TH concentrations. Indeed, circadian changes in the HPT axis activity are not a consequence of oscillation in circulating TH levels. Similarly, during reduced food availability, several components of the HPT axis are down-regulated even in the presence of lower circulating TH levels, suggesting the presence of a regulatory pathway hierarchically higher than the feedback system. This minireview discusses the neural regulation of the HPT axis, focusing on both TH-dependent and -independent pathways and their potential integration.

scholarly journals Differential effects of leptin and refeeding on the fasting-induced decrease of pituitary type 2 deiodinase and thyroid hormone receptor β2 mRNA expression in mice

2006 ◽  
Vol 190 (2) ◽  
pp. 537-544 ◽  
Author(s):  
A Boelen ◽  
J Kwakkel ◽  
X G Vos ◽  
W M Wiersinga ◽  
E Fliers
Keyword(s):  
Thyroid Hormone ◽  
Mrna Expression ◽  
Hormone Receptor ◽  
Thyroid Hormone Receptor ◽  
Hormone Metabolism ◽  
Serum Leptin ◽  
Thyroid Hormone Metabolism ◽  
Hpt Axis ◽  
As Effects

Profound changes in thyroid hormone metabolism occur in the central part of the hypothalamus–pituitary–thyroid (HPT) axis during fasting. Hypothalamic changes are partly reversed by leptin administration, which decreases during fasting. It is unknown to what extent leptin affects the HPT axis at the level of the pituitary. We, therefore, studied fasting-induced alterations in pituitary thyroid hormone metabolism, as well as effects of leptin administration on these changes. Because refeeding rapidly increased serum leptin, the same parameters were studied after fasting followed by refeeding. Fasting for 24 h decreased serum T3 and T4 and pituitary TSHβ, type 2deiodinase (D2), and thyroid hormone receptor β2 (TRβ2) mRNA expression. The decrease in D2 and TRβ2 mRNA expression was prevented when 20 μg leptin was administered twice during fasting. By contrast, the decrease in TSHβ mRNA expression was unaffected. A single dose of leptin given after 24 h fasting did not affect decreased TSHβ, D2, and TRβ2 mRNA expression, while 4 h refeeding resulted in pituitary D2 and TRβ2 mRNA expression as observed in control mice. Serum leptin, T3, and T4 after refeeding were similar compared with leptin administration. We conclude that fasting decreases pituitary TSHβ, D2, and TRβ2 mRNA expression, which (with the exception of TSHβ) can be prevented by leptin administration during fasting. Following 24 h fasting, 4 h refeeding completely restores pituitary D2 and TRβ2 mRNA expression, while a single leptin dose is ineffective. This indicates that other postingestion signals may be necessary to modulate rapidly the fasting-induced decrease in pituitary D2 and TRβ2 mRNA expression.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Beyond the fixed setpoint of the hypothalamus–pituitary–thyroid axis

2014 ◽  
Vol 171 (5) ◽  
pp. R197-R208 ◽  
Author(s):  
Eric Fliers ◽  
Andries Kalsbeek ◽  
Anita Boelen
Keyword(s):  
Thyroid Hormone ◽  
Negative Feedback ◽  
Thyroid Hormone Receptor ◽  
Feedback Regulation ◽  
Tissue Level ◽  
Serum Concentrations ◽  
Negative Feedback Regulation ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Hpt Axis

The hypothalamus–pituitary–thyroid (HPT) axis represents a classical example of an endocrine feedback loop. This review discusses dynamic changes in HPT axis setpoint regulation, identifying their molecular and cellular determinants, and speculates about their functional role. Hypothalamic thyrotropin-releasing hormone neurons were identified as key components of thyroid hormone (TH) setpoint regulation already in the 1980s, and this was followed by the demonstration of a pivotal role for the thyroid hormone receptor beta in negative feedback of TH on the hypothalamic and pituitary level. Gradually, the concept emerged of the HPT axis setpoint as a fixed entity, aiming at a particular TH serum concentration. However, TH serum concentrations appear to be variable and highly responsive to physiological and pathophysiological environmental factors, including the availability or absence of food, inflammation and clock time. During food deprivation and inflammation, TH serum concentrations decrease without a concomitant rise in serum TSH, reflecting a deviation from negative feedback regulation in the HPT axis. Surprisingly, TH action in peripheral organs in these conditions cannot be simply predicted by decreased serum TH concentrations. Instead, diverse environmental stimuli have differential effects on local TH metabolism, e.g. in liver and muscle, occurring quite independently from decreased TH serum concentrations. The net effect of these differential local changes is probably a major determinant of TH action at the tissue level. In sum, hypothalamic HPT axis setpoint regulation as well as TH metabolism at the peripheral organ level is flexible and dynamic, and may adapt the organism in an optimal way to a range of environmental challenges.

Endocrine control of smoltification in anadromous salmonids

1986 ◽  
Vol 108 (2) ◽  
pp. 313-319 ◽  
Author(s):  
M. G. Barron
Keyword(s):  
Thyroid Hormone ◽  
Endocrine System ◽  
Endocrine Glands ◽  
Endocrine Control ◽  
Regulatory Ability ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Recent Attention ◽  
Endocrine Tissues

ABSTRACT The parr–smolt transformation (smoltification) of juvenile anadromous salmonids involves a morphological, physiological and behavioural metamorphosis of the fish from a freshwater-adapted form to a saltwater-adapted form. Several endocrine glands are activated during the period of smoltification, including pituitary, thyroid, and interrenal tissues. The pituitary-thyroid axis appears to be the endocrine system most directly involved in controlling smoltification. A plasma thyroid hormone surge occurs during smoltification which appears to influence various tissues and other endocrine systems, and to induce the well-documented developmental changes associated with smoltification. The pituitary-interrenal axis has been implicated in several smoltification-related events, including development of hypo-osmotic regulatory ability. A plasma cortisol surge closely follows the thyroid hormone surge during smoltification, but in contrast to anuran metamorphosis, the peaks do not coincide. Despite recent attention, the role of the corticosteroids in development of hypo-osmotic regulatory ability remains unclear. The other endocrine tissues of the salmonids appear to be acting trophically with the thyroid hormones, or to have little involvement in the control of smoltification. J. Endocr. (1986) 108, 313–319

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