Effects of Hyperosmolality on Na, K-ATPase Gene Expression in Vascular Smooth Muscle Cells

Effects of Hyperosmolality on Na, K-ATPase Gene Expression in Vascular Smooth Muscle Cells Cultured vascular smooth muscle cells (VSMC) from rat thoracic aortas were exposed to hyperosmotic media to determine the effects on Na, K-ATPase α1- and β1-mRNA expression. Hyperosmotic media (500 mOsm/kgH2O) supplemented with glucose or mannitol increased α1-mRNA levels threefold at 24 hr and β1-mRNA levels sevenfold at 12 hr. In sharp contrast, hyperosmotic urea medium had no effect at any time. Both the protein synthesis inhibitor cycloheximide and the RNA transcription inhibitor actinomycin D reduced α1- and β1-mRNA upregulation induced by hyperosmotic glucose or mannitol media. Protein kinase C (PKC) inhibitors (staurosporine A or calphostin C) or tyrosine kinase (TK) inhibitors (genistein or herbimycin A) had no effect on the α1-mRNA upregulation induced by hyperosmotic glucose or mannitol media. Hyperosmotic glucose or mannitol media (500 mOsm/kgH2O) significantly increased α1- and β1-subunit protein levels and Na, K-ATPase activity, whereas hyperosmotic urea medium had no effect. Transfection experiments with the 5′-flanking sequences of the α1- or β1-subunit genes linked to the luciferase reporter gene revealed that hyperosmolar glucose medium increased luciferase activity 2.9- and 3.7-fold, respectively. Similarly, hyperosmotic mannitol medium increased such activity 2.7- and 3.4-fold, respectively. These results demonstrate that: (i) hyperosmolality induced by the poorly permeating solutes (glucose and mannitol) stimulates α1- and β1-mRNA accumulation, α1- and β1-subunit protein accumulation, and Na, K-ATPase activity, whereas the rapidly permeating solute (urea) has no effect; (ii) the upregulation of α1- and β1-mRNA in response to hyperosmotic glucose or mannitol media requires, at least in part, de novo synthesis of intermediate regulatory proteins; (iii) the hyperosmolality-induced α1-mRNA upregulation occurs through PKC- and TK-independent mechanisms, whereas the hyperosmolality-induced β1-mRNA upregulation occurs through activation of PKC and TK; and (iv) hyperosmolality induced by glucose or mannitol increases promoter activities of the α1- and β1-subunit genes. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Effects of Hyperosmolality on Na, K-ATPase Gene Expression in Vascular Smooth Muscle Cells

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