Suppression of Canine ATP Binding Cassette ABCB1 in Madin-Darby Canine Kidney Type II Cells Unmasks Human ABCG2-Mediated Efflux of Olaparib.

Endogenous canine ATP binding cassette B1 (cABCB1) is expressed abundantly in Madin-Darby canine kidney type II (MDCKII) cells, and its presence often complicates phenotyping of the transport process. Errors in estimating the corrected efflux ratio (cER), as a result of the variable expression of cABCB1, were examined for the dual substrates of ABCB1 and ABCG2 in MDCKII cells expressing human ABCG2 (hABCG2). cABCB1 mRNA and protein expression was 60% and 55% lower, respectively, in MDCKII cells expressing hABCG2 compared with the wild type, suggesting that the expression of endogenous cABCB1 became variable after the expression of hABCG2.

Identification of the primary determining factor(s) governing the oral absorption of edaravone in rats.

This study was performed to determine the primary factor(s) governing the oral absorption of edaravone, a novel anti-oxidant for the treatment of amyotrophic lateral sclerosis, in rats. While the aqueous solubility of edaravone widely varied depending on the vehicle used, the oral bioavailability of the drug was not low when it was adequately solubilized, as evidenced by the fact that the oral exposure was high (in terms of the absolute bioavailability of 50-90%) at all dose ranges (i.e.

The conditional stimulation of rat organic cation transporter 2, but not its human ortholog, by mesoridazine: the possibility of the involvement of the high-affinity binding site of the transporter in the stimulation.

Objectives: To study the functional consequences of the human and rat forms of OCT2 in the presence of phenothiazines.

Methods: MDCK cells expressing human or rat OCT2 were established, and MPP+ transport was determined by uptake assays. Concentration dependency was studied for the stimulatory/inhibitory effects of phenothiazines on MPP+ transport.