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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1987-9-4
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pubmed:abstractText |
The transport of histidine and glutamine via system N in cultured hepatocytes was found to be subject to hormonal control. This long-term regulation showed the following characteristics. The transport capacity for histidine and glutamine (system N) increased slowly in response to the combination of dexamethasone and insulin to about 4-fold that of controls after 18-30 h. A similar time course was found for the stimulation of system N (2.5-fold) by dexamethasone and glucagon. In contrast the uptake of alpha-aminoisobutyric acid (system A) was rapidly stimulated 3-fold by dexamethasone and insulin and 5-fold by dexamethasone and glucagon within 3-6 h but decreased towards control rates after 24 h of cultivation in minimal essential medium. Dexamethasone, insulin and glucagon each stimulated glutamine uptake about 2-fold in cultures maintained in W/AB 77 medium, while the combination of dexamethasone with either glucagon or insulin resulted in a 3-4-fold increase. Dexamethasone was most effective at about 0.1 microM. Higher concentrations were less efficient. Insulin reached its optimal effect at concentrations above 1 microM. Kinetic analysis revealed that the increased capacity of glutamine transport in response to hormones was due to an increase in Vmax, while Km was essentially unchanged. The hormone-induced stimulation of system N was prevented by cycloheximide. The induced uptake of glutamine was inhibited by excess amounts of asparagine and histidine but not of alpha-methylaminoisobutyric acid or cysteine. These results clearly differentiate the hormonal regulation of system N from that of system A.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Dexamethasone,
http://linkedlifedata.com/resource/pubmed/chemical/Glucagon,
http://linkedlifedata.com/resource/pubmed/chemical/Glutamine,
http://linkedlifedata.com/resource/pubmed/chemical/Histidine,
http://linkedlifedata.com/resource/pubmed/chemical/Insulin
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pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
166
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
339-44
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:3301340-Amino Acids,
pubmed-meshheading:3301340-Animals,
pubmed-meshheading:3301340-Biological Transport,
pubmed-meshheading:3301340-Cells, Cultured,
pubmed-meshheading:3301340-Dexamethasone,
pubmed-meshheading:3301340-Glucagon,
pubmed-meshheading:3301340-Glutamine,
pubmed-meshheading:3301340-Histidine,
pubmed-meshheading:3301340-Insulin,
pubmed-meshheading:3301340-Kinetics,
pubmed-meshheading:3301340-Liver,
pubmed-meshheading:3301340-Male,
pubmed-meshheading:3301340-Rats,
pubmed-meshheading:3301340-Rats, Inbred Strains
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pubmed:year |
1987
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pubmed:articleTitle |
Hormonal regulation of amino acid transport system N in primary cultures of rat hepatocytes.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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