A survey is given on a few selected cell culture models that are used for t
ransport studies. They are characterised for growth, transcellular electric
al resistance and cytoarchitecture. The importance of standardisation in vi
ew of their use as transport models is documented. Their potential for stud
ies on passive permeation and P-glycoprotein-mediated transport is explored
and related to published data. Transport studies are presented that were p
erformed in a two-chamber set-up, the Costar(R) "vertical diffusion system"
. A series of non-homologous compounds showed similar permeability data (P-
app) in the different cell cultures. The origin of the cell type had no rem
arkable influence on passive transcellular permeation. MDCK cells, an epith
elial cell line of canine kidney origin, are perfectly suited to screen for
passive permeation. They have low expression of transporter proteins and l
ow metabolic activity. In general, they probably represent the best-known e
pithelial cell line with respect to genetics as well as lipid and protein c
omposition. MDCK cells are easy to handle. Transport experiments can be don
e between 7 and 14 days after seeding, when the stationary growth phase is
reached. To screen for P-glycoprotein substrates, efflux and uptake studies
were performed with mdr1-transfected MDCK cells (MDR1-MDCK) in a one-chamb
er system in the presence or absence of verapamil or cyclosporin A as inhib
itor. Evidence is presented why the transfected cells, which express large
amounts of P-glycoprotein, are not suitable for two-chamber transport studi
es. (C) 2000 Elsevier Science B.V. All rights reserved.