Concurrent and Independent HCO− 3 and Cl− Secretion in a Human Pancreatic Duct Cell Line (CAPAN-1)

Concurrent and Independent HCO− 3 and Cl− Secretion in a Human Pancreatic Duct Cell Line... The present study investigated both HCO− 3 and Cl− secretions in a human pancreatic duct cell line, CAPAN-1, using the short-circuit current (I sc ) technique. In Cl−/HCO− 3-containing solution, secretin (1 μm) or forskolin (10 μm) stimulated a biphasic rise in the I sc which initially reached a peak level at about 3 min and then decayed to a plateau level after 7 min. Removal of external Cl− abolished the initial transient phase in the forskolin-induced I sc while the plateau remained. In HCO− 3/CO2-free solution, on the contrary, only the initial transient increase in I sc was prominent. Summation of the current magnitudes observed in Cl−-free and HCO− 3-free solutions over a time course of 10 min gave rise to a curve which was similar, both in magnitude and kinetics, to the current observed in Cl−/HCO− 3-containing solution. Removal of external Na+ greatly reduced the initial transient rise in the forskolin-induced I sc response, and the plateau level observed under this condition was similar to that obtained in Cl−-free solution, suggesting that Cl−-dependent I sc was also Na+-dependent. Bumetanide (50 μm), an inhibitor of the Na+-K+-2Cl− cotransporter, and Ba2+ (1 mm), a K+ channel blocker, could reduce the forskolin-induced I sc obtained in Cl−/HCO− 3-containing or HCO− 3-free solution. However, they were found to be ineffective when external Cl− was removed, indicating the involvement of these mechanisms in Cl− secretion. On the contrary, the HCO− 3-dependent (in the absence of external Cl−) forskolin-induced I sc could be significantly reduced by carbonic anhydrase inhibitor, acetazolamide (45 μm). Basolateral application of amiloride (100 μm) inhibited the I sc ; however, a specific Na+-H+ exchanger blocker, 5-N-methyl-N-isobutylamiloride (MIA, 5–10 μm) was found to be ineffective, excluding the involvement of the Na+-H+ exchanger. However, an inhibitor of H+-ATPase, N-ethylmaleimide did suppress the I sc (IC50= 22 μm). Immunohistochemical studies also confirmed the presence of a vacuolar type of H+-ATPase in these cells. H2DIDS (100 μm), an inhibitor of Na+-HCO− 3 cotransporter, was without effect. Apical addition of Cl− channel blocker, diphenylamine-2,2′-dicarboxylic acid (DPC, 1 mm), but not disulfonic acids, DIDS (100 μm) or SITS (100 μm), exerted an inhibitory effect on both Cl− and HCO− 3-dependent forskolin-induced I sc responses. Histochemical studies showed discrete stainings of carbonic anhydrase in the monolayer of CAPAN-1 cells, suggesting that HCO− 3 secretion may be specialized to a certain population of cells. The present results suggest that both HCO− 3 and Cl− secretion by the human pancreatic duct cells may occur concurrently and independently. The Journal of Membrane Biology Springer Journals

Concurrent and Independent HCO− 3 and Cl− Secretion in a Human Pancreatic Duct Cell Line (CAPAN-1)

Loading next page...
Copyright © Inc. by 1998 Springer-Verlag New York
Life Sciences; Biochemistry, general; Human Physiology
Publisher site
See Article on Publisher Site

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.

DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches


Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.



billed annually
Start Free Trial

14-day Free Trial