Physiological and cytotoxic effects of Ca2+ ionophores on caco-2 paracellular permeability: Relationship of 45ca2+ efflux to 51Cr release

Michael J. Rutten, J. Nita Cogburn, Charles S. Schasteen, Travis Solomon

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The human intestinal cell line, Caco-2, and the Ca2+ ionophores, A23187 and ionomycin, were used to determine the interrelationships of 45Ca2+ efflux, transepithelial electrical resistance (Rt), and [3H]-mannitol flux to changes in 5lCr release and lactate dehydrogenase (LDH) activity. Treatment of Caco-2 monolayers with ionomycin at concentrations of between 0.25 and 2.50 umol/1 showed similar 45Ca2+ efflux rate constants and coefficients. Analysis of the control and ionomycin-induced 45Ca2+ efflux values showed the data to best fit a three Ca2+ compartmental model. All changes in Caco-2 R, and [3H]-mannitol flux were reversible with no significant increases in 5lCr release with ionomycin concentrations of ≤ 2.5 µmol/1. Caco-2 monolayers treated with ionomycin at concentrations of between 5.0 and 50.0 umol/1 showed rapid non-exponential 45Ca2+ effluxes with irreversible changes in Rt, [3H]-mannitol flux, and significant increases in 51Cr release. There was no change in media LDH activity using either ionomycin or A23187 at concentrations of up to 50 µmol/1 for 60 min. The results of our study show that: (1) disruption of Ca2+ homeostasis in Caco-2 cells will occur with the addition of Ca2+ ionophores at concentrations of > 2.50 µmol/1; (2) high concentrations (> 2.5 µmol/1) of ionomycin will cause non-exponential 45Ca2+ efflux rates with irreversible changes in transcellular Rt and l4C-mannitol flux, and (3) early signs of Ca2+ ionophore-induced damage can be detected by 5lCr release from Caco-2 cells into the media and not by changes in LDH media activity.

Original languageEnglish (US)
Pages (from-to)156-168
Number of pages13
Issue number3
StatePublished - Jan 1 1991
Externally publishedYes


  • A23187
  • Ca efflux
  • Caco-2
  • Cr release
  • Cytotoxic
  • Ionomycin
  • Lactate dehydrogenase
  • Paracellular permeability

ASJC Scopus subject areas

  • Pharmacology


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