Uptake of clozapine into HL-60 promyelocytic leukaemia cells.

Article Details

Citation

Copy to clipboard

Henning U, Loffler S, Krieger K, Klimke A

Uptake of clozapine into HL-60 promyelocytic leukaemia cells.

Pharmacopsychiatry. 2002 May;35(3):90-5.

PubMed ID

12107852 [ View in PubMed

]

Abstract

The atypical antipsychotic, clozapine, exerts superior efficacy in therapy-resistant schizophrenia, but unfortunately induces agranulocytosis with an incidence of 0.8 - 1 %. In this study, we investigated the cellular uptake of clozapine into human promyelocytic leukaemia HL-60 cells using HPLC with electrochemical detection. On incubation with 1.25 to 40 microM clozapine for 30 min, a saturable, energy- and temperature-dependent uptake process takes place (K m = 18.8 microM, k cat = 1.36 nmol/5 min/mg protein at 37 degrees C). This suggests membrane passage of clozapine by a carrier mechanism. 10 microM Indatraline, an inhibitor of dopamine, noradrenaline and serotonin (5-HT) reuptake, but not the selective 5-HT reuptake inhibitor fluvoxamine, markedly reduced the transport of clozapine by 62 %, whereas addition of 10 mM glucose to the incubation medium increased intracellular clozapine concentrations by 28 %. Since cyclosporine A, vinblastine or verapamil up to a final concentration of 10 microM did not alter the intracellular accumulation of clozapine, an involvement of P-glycoprotein seems to be unlikely. In summary, clozapine uptake into HL-60 cells meets criteria of an active unidirectional transport. Its molecular correlates remain to be established.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Vinblastine	P-glycoprotein 1	Protein	Humans	Unknown	Substrate Inhibitor Inducer	Details