A Role For 11‐Deoxycortisol In The Regulation Of Tight Junction Permeability In An Extant Agnathan
Bibliographic record
Abstract
Corticosteroid hormones are important regulators of paracellular permeability across vertebrate epithelia. In aquatic vertebrates such as teleost fishes, cortisol reduces the paracellular permeability of the gill epithelium, which in a freshwater (FW) environment has been proposed to contribute to reduced passive ion loss under conditions of environmental or systemic perturbation. However, it is not known whether corticosteroids contribute to the regulated movement of solutes across the paracellular pathway in less derived vertebrates, such as agnathans. This gap in knowledge speaks to the difficulty of pinning down the identity of corticosteroid hormones in agnathans. But recent studies have revealed that 11‐deoxycortisol is the only circulating corticosteroid with high affinity and specificity to the sea lamprey corticosteroid receptor. This knowledge now presents us with an opportunity to examine whether 11‐deoxycortisol contributes to the regulation of paracellular ion transport in sea lamprey. Given the strong link between corticosteroids and paracellular solute movement across epithelia of more derived fishes, as well as other vertebrates, it can be hypothesized that 11‐deoxycortisol will play a similar role in the lamprey. Using the stenohaline FW larval form of the sea lamprey, the objectives of this study were to examine the dose‐dependent effects of 11‐deoxycortisol on: (1) endpoints of salt and water balance and (2) the molecular physiology of the larval lamprey TJ complex in iono/osmoregulatory organs such as the gill and kidney. Results indicated that 11‐deoxycortisol treatment of larval sea lamprey dose‐dependently altered endpoints of salt and water balance as well as the abundance of select TJ proteins. Therefore a third objective of this study was to examine whether changes brought about by 11‐deoxycortisol are beneficial to larval lamprey in terms of coping with ionoregulatory disturbance (i.e. abrupt exposure to an ion deficient environment). While data on the molecular physiology of the lamprey TJ complex suggests that the changes produced by 11‐deoxycortisol are useful for ion retention in a hyposmotic or ion‐deficient environment, net flux of Na+ and Cl‐ upon abrupt exposure to ion‐poor water paradoxically suggest that transepithelial solute permeability is greater following 11‐deoxycortisol treatment. Overall, data from these studies provide evidence to support the hypothesis that 11‐deoxycortisol contributes to the regulation of TJ permeability in an extant FW larval agnathan, but this may differ from the role that corticosteroids such as cortisol play in more derived fishes. Support or Funding Information This research was supported by Natural Sciences and Engineering Research Council of Canada.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".