Mechanisms of electrolyte transport across the endometrium. I. Regulation by PGF and cAMP

Alisen E. Vetter, Scott M. O'Grady

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22 Scopus citations

Abstract

The purpose of this study was to characterize the transport mechanisms in endometrial epithelial cells that are responsible for regulation of Na and K concentrations in uterine luminal fluid. Porcine endometrial tissues were mounted in Ussing chambers and bathed in plasmalike Ringer solution. The mean basal short-circuit current (Isc) was 40 μA/cm2, and the mean tissue conductance was 3.6 mS/cm2. Addition of amiloride to the luminal solution inhibited 86% of the basal Isc. Concentration-response experiments using amiloride analogues showed a rank order of potency of benzamil > amiloride > 5-(N-methyl-N-isobutyl)-amiloride in blocking the Isc, with no response to ethylisopropylamiloride. Na channel immunoreactivity was localized to the apical membrane of surface epithelial cells. The Na-to-K selectivity ratio of the amiloride-sensitive Na channel was calculated to be 6.4:1. Prostaglandin (PG) F or 8-(chlorophenylthio)-adenosine 3′,5′-cyclic monophosphate (CPT-cAMP) added to the luminal solution stimulated a twofold increase in Isc that was inhibited by pretreatment with amiloride. Experiments using both amphotericin B-permeabilized tissues and intact tissues showed that PGF and cAMP increased Na absorption by activation of basolateral K channels. Treatment of the luminal solution with 4-aminopyridine produced an effect on Isc that was consistent with block of K secretion and a subsequent decrease in Na absorption. These experiments showed that Na and K transport are tightly coupled processes occurring under basal conditions in surface endometrial epithelial cells and that these processes are regulated by PGF and cAMP.

Original languageEnglish (US)
Pages (from-to)C663-C672
JournalAmerican Journal of Physiology - Cell Physiology
Volume270
Issue number2 39-2
DOIs
StatePublished - Feb 1996

Keywords

  • Epithelial ion transport
  • Potassium secretion
  • Prostaglandins
  • Sodium absorption
  • Uterus

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