Fluid secretion in interlobular ducts isolated from guinea-pig pancreas

H. Ishiguro, S. Naruse, M. C. Steward, M. Kitagawa, S. B.H. Ko, T. Hayakawa, R. M. Case

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1. Pancreatic HCO3- and fluid secretion were studied by monitoring luminal pH (pH(L)) and luminal volume simultaneously in interlobular duct segments isolated from guinea-pig pancreas. The secretory rate and HCO3- flux were estimated from fluorescence images obtained following microinjection of BCECF-dextran (70 kDa, 20 μM) into the duct lumen. 2. Ducts filled initially with a Cl--rich solution swelled steadily (2.0 nl min-1 mm-2) when HCO3-/CO2 was introduced, and the luminal pH increased to 8.08. When Cl- was replaced by glucuronate, spontaneous fluid secretion was reduced by 75%, and pH(L) did not rise above 7.3. 3. Cl--dependent spontaneous secretion was largely blocked by luminal H2DIDS (500 μM). We conclude that, in unstimulated ducts, HCO3- transport across the luminal membrane is probably mediated by Cl--HCO3- exchange. 4. Secretin (10 nM) and forskolin (1μM ) both stimulated HCO3- and fluid secretion. The final value of pH(L) (8.4) and the increase in secretory rate (1.5 nl min-1 mm-2) after secretin stimulation were unaffected by substitution of Cl-. 5. The Cl--independent component of secretin-evoked secretion was not affected by luminal H2DIDS. This suggests that a Cl--independent mechanism provides the main pathway for luminal HCO3- transport in secretin-stimulated ducts. 6. Ducts filled initially with a HCO3--rich fluid (125 mM HCO3-, 23 mM Cl-) secreted Cl--rich fluid while unstimulated. This became HCO3--rich when secretin was applied. 7. Addition of H2DIDS and MIA (10 μM) to the bath reduced the secretory rate by 56 and 18%, respectively. Applied together they completely blocked fluid secretion. We conclude that basolateral HCO3- transport is mediated mainly by Na+-HCO3- cotransport rather than by Na+-H+ exchange.

元の言語English
ページ(範囲)407-422
ページ数16
ジャーナルJournal of Physiology
511
発行部数2
DOI
出版物ステータスPublished - 1998 9 1

ASJC Scopus subject areas

  • Physiology

フィンガープリント Fluid secretion in interlobular ducts isolated from guinea-pig pancreas' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

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    Ishiguro, H., Naruse, S., Steward, M. C., Kitagawa, M., Ko, S. B. H., Hayakawa, T., & Case, R. M. (1998). Fluid secretion in interlobular ducts isolated from guinea-pig pancreas. Journal of Physiology, 511(2), 407-422. https://doi.org/10.1111/j.1469-7793.1998.407bh.x