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rdf:type |
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lifeskim:mentions |
umls-concept:C0002565,
umls-concept:C0014442,
umls-concept:C0018966,
umls-concept:C0038187,
umls-concept:C0041256,
umls-concept:C0205263,
umls-concept:C0441655,
umls-concept:C0441712,
umls-concept:C0851285,
umls-concept:C1158774,
umls-concept:C1627358,
umls-concept:C1882726,
umls-concept:C2349975
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pubmed:issue |
3
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pubmed:dateCreated |
1983-1-27
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pubmed:abstractText |
1. Rat liver tryptophan pyrrolase activity is enhanced by a hormonal-type mechanism during the first 2 days of starvation and by a substrate-type mechanism during the subsequent 2 days. 5-Aminolaevulinate synthase activity is also enhanced during the first 2 days of starvation, but returns thereafter to values resembling those observed in the fed rat. Treatments that prevent or reversé the enhancement of tryptophan pyrrolase activity in 24-48h-starved rats also abolish that of 5-aminolaevulinate synthase activity. Starvation of guinea pigs, which does not enhance the pyrrolase activity, also fails to alter that of the synthase. It is suggested that the decrease in 5-aminolaevulinate synthase activity in 72-96h-starved rats represents negative-feedback repression of synthesis, possibly involving tryptophan participation, whereas the enhancement observed in 24-48h-starved animals is caused by positive-feedback induction secondarily to increased utilization of the regulatory-haem pool by the newly synthesized apo-(tryptophan pyrrolase). 2. Glucose, fructose and sucrose abolish the 24h-starvation-induced increases in rat liver tryptophan pyrrolase and 5-aminolaevulinate synthase activities. Cortisol reverses the glucose effect on 5-aminolaevulinate synthase activity, presumably by enabling pyrrolase to re-utilize the regulatory-haem pool after induction of synthesis of this latter enzyme. 3. The impaired ability of 2-allyl-2-isopropylacetamide to enhance markedly 5-aminolaevulinate synthase activity in 24h-starved rats treated with glucose is associated with a failure of the porphyrogen to cause loss of tryptophan pyrrolase haem. Cortisol restores the ability of the porphyrogen to destroy tryptophan pyrrolase haem and to enhance markedly 5-aminolaevulinate synthase activity, presumably by enhancing tryptophan pyrrolase synthesis and, thereby, its re-utilization of the regulatory-haem pool. It is tentatively suggested that 2-allyl-2-isopropylacetamide destroys the above pool only after it has become bound to (or utilized by) apo-(tryptophan pyrrolase).
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-1098646,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-13743276,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-14127691,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-14148842,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-14169218,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4148070,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-41487,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4149393,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4400410,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4429542,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-446865,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4762758,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-4799079,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-5656975,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-5773289,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-5922957,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-6027463,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-6270470,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-6446903,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-7092847,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-7236220,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-7326008,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-7396848,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-8041,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-911321,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-970951,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7150255-970967
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
206
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
441-9
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:7150255-5-Aminolevulinate Synthetase,
pubmed-meshheading:7150255-Acetamides,
pubmed-meshheading:7150255-Allylisopropylacetamide,
pubmed-meshheading:7150255-Animals,
pubmed-meshheading:7150255-Enzyme Induction,
pubmed-meshheading:7150255-Fructose,
pubmed-meshheading:7150255-Glucose,
pubmed-meshheading:7150255-Heme,
pubmed-meshheading:7150255-Hydrocortisone,
pubmed-meshheading:7150255-Liver,
pubmed-meshheading:7150255-Male,
pubmed-meshheading:7150255-Rats,
pubmed-meshheading:7150255-Rats, Inbred Strains,
pubmed-meshheading:7150255-Starvation,
pubmed-meshheading:7150255-Sucrose,
pubmed-meshheading:7150255-Tryptophan Oxygenase
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pubmed:year |
1982
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pubmed:articleTitle |
Tryptophan pyrrolase in haem regulation. The mechanisms of enhancement of rat liver 5-aminolaevulinate synthase activity by starvation and of the glucose effect on induction of the enzyme by 2-allyl-2-isopropylacetamide.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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