Influence of amphotericin B on the sodium pump of porcine lens epithelium

Nicholas A Delamere, William L. Dean, Jeffrey M. Stidam, Amy E. Moseley

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Active transport by Na+-K+-ATPase in the monolayer of lens epithelium is vital for the regulation of sodium and potassium levels within the mass of fiber cells that make up the bulk of the lens. In this study, experiments were conducted using porcine lenses to test whether Na+-K+-ATPase activity in the epithelium is altered when the permeability of lens cell plasma membranes is increased by the ionophore amphotericin B. After 24 h, sodium was significantly (P < 0.01) elevated in lenses exposed to 5 or 10 μM amphotericin B. Amphotericin B stimulated 86Rb uptake, probably through an increase of cytoplasmic sodium concentration due to increased inward sodium leak; the rate of ouabain-sensitive potassium (86Rb) uptake by intact lenses was significantly increased by amphotericin B at 5 μM (P < 0.05) and 10 μM (P < 0.01). After 24 h, the epithelium from lenses exposed to amphotericin B had an Na+-K+-ATPase activity that was more than twofold higher (P < 0.01) than the Na+-K+-ATPase activity in control lenses. By immunoblot, there was an increase in Na+-K+-ATPase catalytic (α) subunit immunoreactive polypeptide in the epithelium of lenses exposed to amphotericin B. The increase stemmed from a marked increase of Na+-K+- ATPase α2-immunoreactive polypeptide but little change in the amount of α1-immunoreactive protein. As judged by immunoblot experiments, the amount of Na+-K+-ATPase β1-immunoreactive polypeptide also appeared to be higher in the epithelium of amphotericin B-treated lenses compared with control lenses. In summary, these results suggest that in response to a permeability challenge with amphotericin B, the porcine lens epithelium is able to increase the activity of Na+-K+-ATPase. The same permeability challenge also appears to stimulate the biosynthesis of Na+-K+-ATPase catalytic subunit as well as glycoprotein subunit polypeptides.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume270
Issue number2 39-2
StatePublished - Feb 1996
Externally publishedYes

Fingerprint

Sodium-Potassium-Exchanging ATPase
Amphotericin B
Lenses
Swine
Epithelium
Adenosine Triphosphatases
Sodium
Permeability
Peptides
Cell membranes
Catalytic Domain
Potassium
Cell Membrane
sodium-translocating ATPase
Active Biological Transport
Biosynthesis
Ionophores
Ouabain
Monolayers
Glycoproteins

Keywords

  • immunoblot
  • membrane transport
  • sodium-potassium-adenosinetriphosphatase

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

Cite this

Influence of amphotericin B on the sodium pump of porcine lens epithelium. / Delamere, Nicholas A; Dean, William L.; Stidam, Jeffrey M.; Moseley, Amy E.

In: American Journal of Physiology - Cell Physiology, Vol. 270, No. 2 39-2, 02.1996.

Research output: Contribution to journalArticle

Delamere, Nicholas A ; Dean, William L. ; Stidam, Jeffrey M. ; Moseley, Amy E. / Influence of amphotericin B on the sodium pump of porcine lens epithelium. In: American Journal of Physiology - Cell Physiology. 1996 ; Vol. 270, No. 2 39-2.
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