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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
11
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pubmed:dateCreated |
1992-7-1
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pubmed:abstractText |
Erythrocyte insulin-like growth factor I (IGF-I) and insulin receptors were characterized in 10 normal prepubertal children (5 girls and 5 boys) aged 4-11 yrs and 10 normal adults (4 women and 6 men) aged 32-47 yrs. erythrocytes were purified from 5 ml of blood by Ficoll-Paque gradient centrifugation. Reticulocytes count in the erythrocyte suspensions were lower than 1%. Insulin and IGF-I binding assays were performed simultaneously. Maximal percent binding of [125I] labelled IGF-I was significantly higher in prepubertal children than in adults (8.7 +/- 0.7% versus 6.2 +/- 0.5% at a concentration of 5 x 10(9) erythrocytes/ml). Scatchard analysis revealed the high affinity constant was better in prepubertal children (Ka = 4.6 +/- 1.3 nM-1 versus 1.8 +/- 0.2 nM-1), whereas the binding capacity was similar (5.8 +/- 1.1 versus 7.7 +/- 0.8 high affinity binding sites/cell). In both groups, unlabelled IGF-I inhibited tracer-binding half maximally at about 1 nM. Insulin was 100-fold less potent. In adults, specific binding of [125I] labelled IGF-I was higher in women (7.6 +/- 0.7%) than in men (5.3 +/- 0.4%). No significant difference was observed in maximal specific binding of [125I] labelled insulin between prepubertal children (8.2 +/- 0.5%) and adults (7.2 +/- 0.7%). In both groups, competition by unlabelled insulin for [125I] labelled insulin binding gave 50% displacement for approximately 0.25 nM and IGF-I was about 80-fold less potent. Both IGF-I and insulin binding parameters were not significantly correlated with plasma hormone levels. In prepubertal children, the high-affinity IGF-I receptors number decreased with increasing high-affinity insulin receptors number.(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0018-5043
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
23
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
545-52
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:1816066-Adult,
pubmed-meshheading:1816066-Child,
pubmed-meshheading:1816066-Child, Preschool,
pubmed-meshheading:1816066-Erythrocytes,
pubmed-meshheading:1816066-Female,
pubmed-meshheading:1816066-Humans,
pubmed-meshheading:1816066-Insulin,
pubmed-meshheading:1816066-Insulin-Like Growth Factor I,
pubmed-meshheading:1816066-Iodine Isotopes,
pubmed-meshheading:1816066-Male,
pubmed-meshheading:1816066-Middle Aged,
pubmed-meshheading:1816066-Protein Binding,
pubmed-meshheading:1816066-Puberty,
pubmed-meshheading:1816066-Receptor, Insulin
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pubmed:year |
1991
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pubmed:articleTitle |
Insulin-like growth factor I (IGF-I) and insulin binding to erythrocytes of normal prepubertal children and adults.
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pubmed:affiliation |
Laboratoire de Physiologie, Biologie de la Reproduction et du Développement, Clermont-Ferrand I, France.
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pubmed:publicationType |
Journal Article,
Comparative Study
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