Drug Transport Mediated by SLC Transporters Using Xenopus Laevis Oocytes

Drug Transport Mediated by SLC Transporters Using Xenopus Laevis Oocytes 

To study liver (or kidney) specific uptake of endogenous compounds or pharmaceutical drug oocytes expressing single uptake transporters at a very high expression level can easily be used. Km and K, constants can be calculated and compared with in vivo PK data (e.g. saturation levels). 

Xenopus laevis frogs can be purchased from the African Xenopus Facility, Knysna, Republic of South Africa, and are kept in a constant alternating 12-hour light (6 30 am to 6 30 pm)/dark cycle. 

Inhibition constants (K ) are estimated by Dixon plot analysis and linear regression using ordinary least squares. Apparent Km values are estimated by nonlinear regression (Vavricka et al. 2002). 

Standard substrate bromosulfophthalein (BSP) was used with OATP-C, 8, -B and -A expressing oocytes (Vavricka et al. 2002) and its Km values were determined. For OATP-C they measured a Km of 300 nM, for OATP8 400 nM, for OATP-B 700 nM and 20 tiM forOATP-A. 

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