Journal of Comparative Physiology B

, Volume 175, Issue 1, pp 57–66

A new method to measure intestinal activity of P-glycoprotein in avian and mammalian species

Authors

  • Adam K. Green
    • Department of Wildlife EcologyUniversity of Wisconsin-Madison
  • David M. Barnes
    • Department of Animal SciencesUniversity of Wisconsin-Madison
    • Department of Wildlife EcologyUniversity of Wisconsin-Madison
Original Paper

DOI: 10.1007/s00360-004-0462-0

Cite this article as:
Green, A.K., Barnes, D.M. & Karasov, W.H. J Comp Physiol B (2005) 175: 57. doi:10.1007/s00360-004-0462-0

Abstract

Permeability-glycoprotein (Pgp) actively exports numerous potentially toxic compounds once they diffuse into the cell membrane of intestinal epithelial cells. We adapted the everted sleeve technique to make the first measures of intestinal Pgp function in an avian species (chicken) and in wild mammalian species, and compared them to laboratory rats. Tissues maintained both structural and functional integrity, and our method offers advantages over other in vitro techniques by using smaller intestinal sections (1 cm), and shorter incubation times (8–12 min). To determine Pgp function, we compared accumulation of [3H]-digoxin in sleeves incubated in Ringer solution with and without a transport-saturating concentration of a competitive inhibitor, cyclosporin A. We demonstrated significant variation in Pgp activity within individuals along the intestine, between populations fed different diets, and between species (laboratory rats had one-third to one-fifth the Pgp activity of wild rodents). In chicken, we also tested the effect of natural metabolites on digoxin accumulation. We found that among flavonoids, genistein (200 μM), found in soy and other legumes, but not quercetin (10, 30, 100, 330 μM) or the 3-β-glycoside isoquercetrin (100 μM), significantly increased digoxin accumulation. Among fungal metabolites, sterigmatocystin (5 μM), but not aflatoxin B1 (5 μM), significantly increased digoxin accumulation.

Keywords

P-glycoproteinEverted sleeveFlavonoidsAflatoxinSterigmatocystin

Abbreviations

ABC

ATP-binding cassette

AFB1

Aflatoxin-B1

CsA

Cyclosporin A

C.V.

Coefficient of variation

DMSO

Dimethyl sulfoxide

GEN

Genistein

ISOQ

Isoquercetrin

MDR

Multi-drug resistance

PEG

Poly-ethylene glycol

Pgp

Permeability-glycoprotein

QUERC

Quercetin

SGLT-1

Sodium-dependent glucose transporter

ST

Sterigmatocystin

Copyright information

© Springer-Verlag 2004