Abstract
The guanylin family of peptides are effective regulators of intestinal physiology in marine teleosts. In the distal intestinal segments, they inhibit or reverse fluid absorption by inhibiting the absorptive shortcircuit current (I<inf>sc</inf>). The present findings demonstrate that mRNA from guanylin and uroguanylin, as well as at least one isoform of the guanylin peptide receptor, apical guanylyl cyclase-C (GC-C), was highly expressed in the intestine and rectum of the Gulf toadfish (Opsanus beta). In the posterior intestine, GC-C, as well as the cystic fibrosis transmembrane conductance regulator and basolateral Na<sup>+</sup>/ K<sup>+</sup>/2Cl<sup>−</sup> cotransporter, which comprise a Cl<sup>−</sup>-secretory pathway, were transcriptionally upregulated in 60 parts per thousand (ppt). The present study also shows that, in intestinal tissues from Gulf toadfish held in 35 ppt, renoguanylin (RGN) expectedly causes net Cl<sup>−</sup> secretion, inhibits both the absorptive Isc and fluid absorption, and decreases HCO<inf>3</inf><sup>−</sup> secretion. Likewise, in intestinal tissues from Gulf toadfish acclimated to 60 ppt, RGN also inhibits the absorptive I<inf>sc</inf> and fluid absorption but to an even greater extent, corresponding with the mRNA expression data. In contrast, RGN does not alter Cl<sup>−</sup> flux and, instead, elevates HCO<sup>−</sup><inf>3</inf> secretion in the 60-ppt group, suggesting increased apical Cl<sup>−</sup>/HCO<sup>−</sup><inf>3</inf> exchange activity by SLC26a6. Overall, these findings reinforce the hypotheses that the guanylin peptide system is important for salinity acclimatization and that the secretory response could facilitate the removal of solids, such as CaCO<inf>3</inf> precipitates, from the intestine.
| Original language | English (US) |
|---|---|
| Pages (from-to) | R399-R409 |
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 309 |
| Issue number | 4 |
| DOIs | |
| State | Published - Aug 18 2015 |
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Keywords
- Fluid Secretion
- HCO<sup>–</sup><inf>3</inf> secretion
- Hypersalinity
- Marine teleost
- Osmoregulation
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
The differential role of renoguanylin in osmoregulation and apical Cl<sup>−</sup>/HCO<sup>−</sup><inf>3</inf> exchange activity in the posterior intestine of the gulf toadfish (Opsanus beta). / Ruhr, Ilan M.; Mager, Edward M.; Takei, Yoshio; Grosell, Martin.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 309, No. 4, 18.08.2015, p. R399-R409.Research output: Contribution to journal › Article
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TY - JOUR
T1 - The differential role of renoguanylin in osmoregulation and apical Cl−/HCO−3 exchange activity in the posterior intestine of the gulf toadfish (Opsanus beta)
AU - Ruhr, Ilan M.
AU - Mager, Edward M.
AU - Takei, Yoshio
AU - Grosell, Martin
PY - 2015/8/18
Y1 - 2015/8/18
N2 - The guanylin family of peptides are effective regulators of intestinal physiology in marine teleosts. In the distal intestinal segments, they inhibit or reverse fluid absorption by inhibiting the absorptive shortcircuit current (Isc). The present findings demonstrate that mRNA from guanylin and uroguanylin, as well as at least one isoform of the guanylin peptide receptor, apical guanylyl cyclase-C (GC-C), was highly expressed in the intestine and rectum of the Gulf toadfish (Opsanus beta). In the posterior intestine, GC-C, as well as the cystic fibrosis transmembrane conductance regulator and basolateral Na+/ K+/2Cl− cotransporter, which comprise a Cl−-secretory pathway, were transcriptionally upregulated in 60 parts per thousand (ppt). The present study also shows that, in intestinal tissues from Gulf toadfish held in 35 ppt, renoguanylin (RGN) expectedly causes net Cl− secretion, inhibits both the absorptive Isc and fluid absorption, and decreases HCO3− secretion. Likewise, in intestinal tissues from Gulf toadfish acclimated to 60 ppt, RGN also inhibits the absorptive Isc and fluid absorption but to an even greater extent, corresponding with the mRNA expression data. In contrast, RGN does not alter Cl− flux and, instead, elevates HCO−3 secretion in the 60-ppt group, suggesting increased apical Cl−/HCO−3 exchange activity by SLC26a6. Overall, these findings reinforce the hypotheses that the guanylin peptide system is important for salinity acclimatization and that the secretory response could facilitate the removal of solids, such as CaCO3 precipitates, from the intestine.
AB - The guanylin family of peptides are effective regulators of intestinal physiology in marine teleosts. In the distal intestinal segments, they inhibit or reverse fluid absorption by inhibiting the absorptive shortcircuit current (Isc). The present findings demonstrate that mRNA from guanylin and uroguanylin, as well as at least one isoform of the guanylin peptide receptor, apical guanylyl cyclase-C (GC-C), was highly expressed in the intestine and rectum of the Gulf toadfish (Opsanus beta). In the posterior intestine, GC-C, as well as the cystic fibrosis transmembrane conductance regulator and basolateral Na+/ K+/2Cl− cotransporter, which comprise a Cl−-secretory pathway, were transcriptionally upregulated in 60 parts per thousand (ppt). The present study also shows that, in intestinal tissues from Gulf toadfish held in 35 ppt, renoguanylin (RGN) expectedly causes net Cl− secretion, inhibits both the absorptive Isc and fluid absorption, and decreases HCO3− secretion. Likewise, in intestinal tissues from Gulf toadfish acclimated to 60 ppt, RGN also inhibits the absorptive Isc and fluid absorption but to an even greater extent, corresponding with the mRNA expression data. In contrast, RGN does not alter Cl− flux and, instead, elevates HCO−3 secretion in the 60-ppt group, suggesting increased apical Cl−/HCO−3 exchange activity by SLC26a6. Overall, these findings reinforce the hypotheses that the guanylin peptide system is important for salinity acclimatization and that the secretory response could facilitate the removal of solids, such as CaCO3 precipitates, from the intestine.
KW - Fluid Secretion
KW - HCO<sup>–</sup><inf>3</inf> secretion
KW - Hypersalinity
KW - Marine teleost
KW - Osmoregulation
UR - http://www.scopus.com/inward/record.url?scp=84939504338&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84939504338&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.00118.2015
DO - 10.1152/ajpregu.00118.2015
M3 - Article
C2 - 26017493
AN - SCOPUS:84939504338
VL - 309
SP - R399-R409
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
SN - 0363-6143
IS - 4
ER -