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The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish
The circadian activity of the hypothalamo-pituitary-adrenal/interrenal (HPA/I) axis is crucial for maintaining vertebrate homeostasis. In mammals, both the principle regulator, corticotropin-releasing hormone (crh) in the hypothalamic paraventricular nucleus (PVN) and the final effector, the glucoco...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2015
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667085/ https://www.ncbi.nlm.nih.gov/pubmed/26696807 http://dx.doi.org/10.3389/fnins.2015.00436 |
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author | Yeh, Chen-Min |
author_facet | Yeh, Chen-Min |
author_sort | Yeh, Chen-Min |
collection | PubMed |
description | The circadian activity of the hypothalamo-pituitary-adrenal/interrenal (HPA/I) axis is crucial for maintaining vertebrate homeostasis. In mammals, both the principle regulator, corticotropin-releasing hormone (crh) in the hypothalamic paraventricular nucleus (PVN) and the final effector, the glucocorticoids show daily rhythmic patterns. While glucocorticoids are the main negative regulator of PVN crh under stress, whether they modulate the PVN crh rhythm under basal condition is unclear in diurnal animals. Using zebrafish larvae, a recently-established diurnal model organism suited for the HPA/I axis and homeostasis research, we ask if glucocorticoid changes are required to maintain the daily variation of PVN crh. We first characterized the development of the HPI axis overtime and showed that the basal activity of the HPI axis is robust and tightly regulated by circadian cue in 6-day old larvae. We demonstrated a negative correlation between the basal cortisol and neurosecretory preoptic area (NPO) crh variations. To test if cortisol drives NPO crh variation, we analyzed the NPO crh levels in glucorcorticoid antagonist-treated larvae and mutants lacking circadian cortisol variations. We showed that NPO crh basal fluctuation is sustained although the level was decreased without proper cortisol signaling in zebrafish. Our data indicates that glucocorticoids do not modulate the basal NPO crh variations but may be required for maintaining overall NPO crh levels. This further suggests that under basal and stress conditions the HPA/I axis activity is modulated differently by glucocorticoids. |
format | Online Article Text |
id | pubmed-4667085 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-46670852015-12-22 The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish Yeh, Chen-Min Front Neurosci Endocrinology The circadian activity of the hypothalamo-pituitary-adrenal/interrenal (HPA/I) axis is crucial for maintaining vertebrate homeostasis. In mammals, both the principle regulator, corticotropin-releasing hormone (crh) in the hypothalamic paraventricular nucleus (PVN) and the final effector, the glucocorticoids show daily rhythmic patterns. While glucocorticoids are the main negative regulator of PVN crh under stress, whether they modulate the PVN crh rhythm under basal condition is unclear in diurnal animals. Using zebrafish larvae, a recently-established diurnal model organism suited for the HPA/I axis and homeostasis research, we ask if glucocorticoid changes are required to maintain the daily variation of PVN crh. We first characterized the development of the HPI axis overtime and showed that the basal activity of the HPI axis is robust and tightly regulated by circadian cue in 6-day old larvae. We demonstrated a negative correlation between the basal cortisol and neurosecretory preoptic area (NPO) crh variations. To test if cortisol drives NPO crh variation, we analyzed the NPO crh levels in glucorcorticoid antagonist-treated larvae and mutants lacking circadian cortisol variations. We showed that NPO crh basal fluctuation is sustained although the level was decreased without proper cortisol signaling in zebrafish. Our data indicates that glucocorticoids do not modulate the basal NPO crh variations but may be required for maintaining overall NPO crh levels. This further suggests that under basal and stress conditions the HPA/I axis activity is modulated differently by glucocorticoids. Frontiers Media S.A. 2015-12-02 /pmc/articles/PMC4667085/ /pubmed/26696807 http://dx.doi.org/10.3389/fnins.2015.00436 Text en Copyright © 2015 Yeh. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Endocrinology Yeh, Chen-Min The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title | The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title_full | The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title_fullStr | The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title_full_unstemmed | The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title_short | The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish |
title_sort | basal npo crh fluctuation is sustained under compromised glucocorticoid signaling in diurnal zebrafish |
topic | Endocrinology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667085/ https://www.ncbi.nlm.nih.gov/pubmed/26696807 http://dx.doi.org/10.3389/fnins.2015.00436 |
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