Body fluid homeostasis of hagfish: origin of vertebrate osmoregulatory ability

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06876
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Morphology/Structure
• Research Institution: Shimane University
• Principal Investigator: Yamaguchi Yoko 島根大学, 学術研究院農生命科学系, 特任助教 (70801827)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: ヌタウナギ / 環境適応 / 体液調節 / 内分泌系 / 腎臓 / 筋肉 / アミノ酸

Outline of Final Research Achievements

Most extant vertebrates possess the remarkable ability to maintain body fluid homeostasis. Our plasma osmolality and ions are of approximately one-third of seawater, which is achieved by osmoregulatory machinaries in the gill and kidney. Among the extant vertebrates, hagfish is the only osmo-ionoconforming animal, similar to marine invertebrates. In the present study, to understand the origin of vertebrate osmoregulatory ability, the renal and branchial functions in hagfish were examined. The results suggest that the hagfish conducts osmoregulation at the single cell level, but not at the organism level. The intracellular accumulation of amino acids seems to be important for overcoming osmotic stress, and the kidney may play a supplementary role in this process.

Free Research Field

比較内分泌学

Academic Significance and Societal Importance of the Research Achievements

ヌタウナギは進化上重要な位置を占める生物だが、生理学研究はきわめて遅れている。本研究では、ヌタウナギの鰓・腎機能の分子基盤について、初めて網羅的なデータを得ることができた。これは、近年ゲノム配列情報が公開されたこととあわせ、本種を「生理学研究の新たなモデル生物」として確立する第一歩となる成果である。また、ヌタウナギの体液調節戦略において、魚介類の旨味成分として知られるアミノ酸が重要であることが示唆された。将来的には、本研究成果の水産分野への応用も期待される。