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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1980-12-16
pubmed:abstractText
Patients with gyrate atrophy of the choroid and retina have 10- to 20-fold increased ornithine concentrations in body fluids and significantly reduced activity of ornithine aminotransferase in lymphocytes and cultured fibroblasts. We administered intravenous arginine to six patients and six controls to study in vivo inhibition by high ornithine concentrations of arginine-glycine transamidinase, the rate-limiting enzyme in creatine synthesis. Serum arginine concentrations curves after administration were similar for the two groups. The increment in serum ornithine was more than three times as great in patients as in controls. The mean half-times in plasma ornithine were 360 and 97 min, respectively. In the patients, the metabolic clearance of ornithine from the extracellular fluid was significantly delayed. Urinary guanidinoacetate excretion rose markedly in all controls, the excretion rate being higher in females. The patients always excreted less than the controls, the differences within the sexes being highly significant. Differences in creatine excretion after administration were less marked. We conclude that in gyrate atrophy patients, formation of guanidinoacetate, creatine, and possibly phosphocreatine is inhibited at the transaminidation step by the high concentrations of ornithine. Deficiency of the high-energy phosphates may underlie the pathogenesis of the eye and muscle atrophies.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9738
pubmed:author
pubmed:issnType
Print
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
684-7
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1980
pubmed:articleTitle
Gyrate atrophy of the choroid and retina with hyperornithinemia. Deficient formation of guanidinoacetic acid from arginine.
pubmed:publicationType
Journal Article