Antifolate transport in L1210 leukemia cells. Kinetic evidence for the non-identity of carriers for influx and efflux.
Biochim Biophys Acta
; 448(3): 505-16, 1976 Oct 19.
Article
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| MEDLINE
| ID: mdl-974145
ABSTRACT
The kinetics of methotrexate transport in L1210 cells are described. Data derived from the measurmenets of initial influx, the complete time-course of uptake, intracellular steady-state level and unidirectional efflux were found to be consistent with a simple empirical equation containing three constants. Properties of the system include the following (1) saturability of initial influx (2) approach to steady state during uptake is exponential; (3) the half-time for drug uptake is independent of external concentration and equal to half-time for efflux; and (4) transport is concentrative at low external concentrations, whereas the reverse is true at high external concentrations. These observations are incorporated into a kinetic model which quantitatively accounts for the data on the basis of the hypothesis that influx and efflux take place via different carriers.
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Banco de datos:
MEDLINE
Asunto principal:
Leucemia L1210
/
Metotrexato
Límite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1976
Tipo del documento:
Article