RESUMO
The influx of 2,4-dichlorophenoxyacetic acid (2,4-D) into Chinese hamster ovary (CHO) cells was studied. The cells mainly took up but did not metabolize the undissociated form of the herbicide. The uptake of 2,4-D was carried out against a concentration gradient and was inhibited by sodium azide and dinitrophenol. The results presented here show that the herbicide influx was an active, energy dependent process. (Na+ + K+)ATPase does not seem to be involved because ouabain, an inhibitor of the enzyme, did not affect the 2,4-D uptake.
Assuntos
Ácido 2,4-Diclorofenoxiacético/farmacocinética , Herbicidas/farmacocinética , Ácido 2,4-Diclorofenoxiacético/toxicidade , 3-O-Metilglucose , Ácidos Aminoisobutíricos/farmacocinética , Animais , Azidas/farmacologia , Transporte Biológico Ativo/fisiologia , Células CHO , Cricetinae , Meios de Cultivo Condicionados , Dinitrofenóis/farmacologia , Inibidores Enzimáticos/farmacologia , Herbicidas/toxicidade , Concentração de Íons de Hidrogênio , Cinética , Metilglucosídeos/farmacocinética , Ouabaína/farmacologia , Fase S/efeitos dos fármacos , Azida Sódica , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidoresRESUMO
It was found that 1 mM 2,4-dichlorophenoxyacetate (2,4-D) inhibited DNA and protein synthesis in Chinese hamster ovary (CHO) cells. When the possible relationship of this phenomenon to the presence of polyamines in the culture medium was investigated, it was found that: (a) the pesticide inhibited ornithine decarboxylase activity; (b) when the concentration of polyamines present in cells treated with the pesticide was determined, the putrescine concentration did not change, and the spermine and spermidine concentration decreased; (c) the addition of spermidine and spermine to CHO cells grown in the presence of 2,4-D normalized DNA and protein synthesis. Putrescine did not have any effect.