Multiple pathways for uptake of paraquat, methylglyoxal bis(guanylhydrazone), and polyamines
The uptake of polyamines, methylglyoxal bis(guanylhydrazone) (MGBG), and paraquat (N,N-dimethyl-4,4'-bipyridylium) into control Chinese hamster ovary (CHO) cells and a mutant CHO cell line selected for resistance to the toxicity of MGBG was examined. In contrast to control CHO cells, the mutant cells had no detectable uptake of (/sup 14/C)-MGBG or any of the polyamines. There was no difference between the two cell lines in the uptake of ..cap alpha..-aminoisobutyric (/sup 3/H-AIB), which indicates that there was no general change in membrane transport processes. The mutant cells were also found to be resistant to the toxicity of paraquat and to have a reduced capability to take up the herbicide. This finding confirms that the uptake of paraquat is necessary for the toxicity of this compound and that the paraquat is taken up by a transport system that also transports MGBG. Competition experiments showed that an excess of unlabeled paraquat inhibited uptake of MGBG and, to a lesser extent, uptake of putrescine and spermidine, but no inhibitory action on spermine uptake could be detected. Studies with type II cells isolated from rat lung also demonstrated uptake of paraquat and spermidine, but paraquat was only a weak inhibitor of spermidine uptake in this system. These results suggest that there may be multiple systems for the uptake of MGBG and polyamines and that paraquat is taken up by at least one but not by all of these systems.
- Research Organization:
- Pennsylvania State Univ. College of Medicine, Hershey (USA)
- OSTI ID:
- 6864435
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 252:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
MEMBRANE TRANSPORT
UPTAKE
BIPYRIDINES
CARBON 14 COMPOUNDS
AMINOBUTYRIC ACID
CHO CELLS
DOSE-RESPONSE RELATIONSHIPS
MUTANTS
PUTRESCINE
SPERMIDINE
SPERMINE
TRITIUM COMPOUNDS
AMINO ACIDS
ANIMAL CELLS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZINES
CARBOXYLIC ACIDS
DRUGS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
NEUROREGULATORS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
550201* - Biochemistry- Tracer Techniques