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Breves JP, Shaughnessy CA. Endocrine control of gill ionocyte function in euryhaline fishes. J Comp Physiol B 2024:10.1007/s00360-024-01555-3. [PMID: 38739280 DOI: 10.1007/s00360-024-01555-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/16/2024] [Accepted: 04/11/2024] [Indexed: 05/14/2024]
Abstract
The endocrine system is an essential regulator of the osmoregulatory organs that enable euryhaline fishes to maintain hydromineral balance in a broad range of environmental salinities. Because branchial ionocytes are the primary site for the active exchange of Na+, Cl-, and Ca2+ with the external environment, their functional regulation is inextricably linked with adaptive responses to changes in salinity. Here, we review the molecular-level processes that connect osmoregulatory hormones with branchial ion transport. We focus on how factors such as prolactin, growth hormone, cortisol, and insulin-like growth-factors operate through their cognate receptors to direct the expression of specific ion transporters/channels, Na+/K+-ATPases, tight-junction proteins, and aquaporins in ion-absorptive (freshwater-type) and ion-secretory (seawater-type) ionocytes. While these connections have historically been deduced in teleost models, more recently, increased attention has been given to understanding the nature of these connections in basal lineages. We conclude our review by proposing areas for future investigation that aim to fill gaps in the collective understanding of how hormonal signaling underlies ionocyte-based processes.
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Affiliation(s)
- Jason P Breves
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA.
| | - Ciaran A Shaughnessy
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, USA
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Link K, Shved N, Serrano N, Akgül G, Caelers A, Faass O, Mouttet F, Raabe O, D’Cotta H, Baroiller JF, Eppler E. Effects of seawater and freshwater challenges on the Gh/Igf system in the saline-tolerant blackchin tilapia (Sarotherodon melanotheron). Front Endocrinol (Lausanne) 2022; 13:976488. [PMID: 36313755 PMCID: PMC9596810 DOI: 10.3389/fendo.2022.976488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Prolactin (Prl) and growth hormone (Gh) as well as insulin-like growth factor 1 (Igf1) are involved in the physiological adaptation of fish to varying salinities. The Igfs have been also ascribed other physiological roles during development, growth, reproduction and immune regulation. However, the main emphasis in the investigation of osmoregulatory responses has been the endocrine, liver-derived Igf1 route and local regulation within the liver and osmoregulatory organs. Few studies have focused on the impact of salinity alterations on the Gh/Igf-system within the neuroendocrine and immune systems and particularly in a salinity-tolerant species, such as the blackchin tilapia Sarotherodon melanotheron. This species is tolerant to hypersalinity and saline variations, but it is confronted by severe climate changes in the Saloum inverse estuary. Here we investigated bidirectional effects of increased salinity followed by its decrease on the gene regulation of prl, gh, igf1, igf2, Gh receptor and the tumor-necrosis factor a. A mixed population of sexually mature 14-month old blackchin tilapia adapted to freshwater were first exposed to seawater for one week and then to fresh water for another week. Brain, pituitary, head kidney and spleen were excised at 4 h, 1, 2, 3 and 7 days after both exposures and revealed differential expression patterns. This investigation should give us a better understanding of the role of the Gh/Igf system within the neuroendocrine and immune organs and the impact of bidirectional saline challenges on fish osmoregulation in non-osmoregulatory organs, notably the complex orchestration of growth factors and cytokines.
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Affiliation(s)
- Karl Link
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Natallia Shved
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Nabil Serrano
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Gülfirde Akgül
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Antje Caelers
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
| | - Oliver Faass
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
| | | | - Oksana Raabe
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Helena D’Cotta
- Institut des Sciences de l’Evolution de Montpellier (ISEM), Université Montpellier, Institut de Recherche pour le Développement (the French National Research Institute for Sustainable Development) (IRD), Ecole Pratique des Hautes Etudes (Practical School of Advanced Studies) (EPHE), Centre National de la Recherche Scientifique (French National Centre for Scientific Research) (CNRS), Unité Mixte de Recherche (Mixed Research Unit) (UMR) 5554, Montpellier, France
- UMR116-Institut des Sciences de l’Evolution de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France
| | - Jean-François Baroiller
- Institut des Sciences de l’Evolution de Montpellier (ISEM), Université Montpellier, Institut de Recherche pour le Développement (the French National Research Institute for Sustainable Development) (IRD), Ecole Pratique des Hautes Etudes (Practical School of Advanced Studies) (EPHE), Centre National de la Recherche Scientifique (French National Centre for Scientific Research) (CNRS), Unité Mixte de Recherche (Mixed Research Unit) (UMR) 5554, Montpellier, France
- UMR116-Institut des Sciences de l’Evolution de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France
| | - Elisabeth Eppler
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
- Institute of Anatomy, University of Bern, Bern, Switzerland
- *Correspondence: Elisabeth Eppler,
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